Photo-cleavable primer compositions and methods of use

ABSTRACT

In one embodiment, the present application discloses a photo-cleavable surface binding compound of the Formula I and Formula II:wherein the variables EG, EG1, SP1, SP2, SP3, Ar and BG are as defined herein. In another embodiment, the application discloses a method for forming a coating on a surface of a substrate using the surface binding compound.

RELATED APPLICATIONS

The present application is a Divisional of U.S. application Ser. No.15/417,924 filed on Jan. 27, 2017 and issued as U.S. Pat. No. 10,689,407on Jun. 2, 2020, which claims the benefit of U.S. ProvisionalApplication No. 62/309,162 filed Mar. 16, 2016 and U.S. ProvisionalApplication No. 62/288,281 filed Jan. 28, 2016, the disclosures of whichare incorporated herein in its entirety.

BACKGROUND

Strong bidentate bonding, such as hydrogen bonding with catecholicgroups, chelation to metals, and metal-oxygen coordination of thecatechols and their applications as primers containing a catecholfunctional group are known in the art. These catecholic compounds formstrong hydrogen bonds and chelating bonds with different minerals andmetal oxide surfaces.

Photo-cleavage of a building block at specific sites has been reportedin patents [e.g., photo-cleavable linkers for oligonucleotides(EP0233053A2), nucleotide (U.S. Pat. No. 5,241,060) for nucleic acidsequence determination (U.S. Pat. No. 5,366,860)] and non-patent reports[e.g., photo-cleavable degradation (depolymerization) of hydrogels (seeZ., Shafiq et al., Bioinspired Underwater Bonding and Debonding onDemand. Angew. Chem., Int. Ed. 51, 4332-4335 (2012)), photocleavabledissociation of block copolymer micelles (see B. Yan et al.,Near-Infrared Light-Triggered Dissociation of Block Copolymer MicellesUsing Upconverting Nanoparticles, J. Am. Chem. Soc. 133, 19714-19717(2011)) and DNA labels (see B. Nie et al., Surface invasive cleavageassay on a maskless light-directed diamond DNA microarray forgenome-wide human SNP mapping, Analyst 140, 4549-4557 (2015)]. To date,there appears to be no reports on the use of a photo-cleavable primerfor debonding or cleaving of adhesives; although ultraviolet(UV)-initiated photo-cleavable co-monomer has been claimed as one of theingredients in a dental composite (PCT/US2007/014158) and copolyesternetwork (see S. M. June et al., Photoactive Polyesters Containingo-Nitro Benzyl Ester Functionality for Photodeactivatable Adhesion, TheJournal of Adhesion 89, 548-558 (2013). When crosslinked/cured adhesivesare used, the debonding of adhesives is very difficult or seeminglyimpossible without breakage or fracture of the glued/bonded/adheredobjects or the surface of the objects.

SUMMARY OF THE INVENTION

In contrast to prior publications using UV irradiation to depolymerizedental composites (PCT/US2007/014158) or copolymer, the presentapplication discloses a cleavage or debonding process between amineral/metal/oxide-containing surface and a (co)polymer/adhesive/resinsurface by specifically cleaving the primer compound using infrared(IR), ultraviolet (UV) and/or a combination of IR and UV irradiation. Inone embodiment, the application discloses photocleavable primers fordebonding of adhesives by cleaving a covalent bond of the primercompound. In one aspect, the debonding is controlled and selective on aparticular position on the primer compound, and does not result in abreakage or an uncontrolled depolymerization of the primer or adhesiveand/or substrate surface. In one particular aspect, the presenttechnology is applicable to dental adhesives.

In one embodiment, the present application discloses a photo-cleavablesurface binding compound of the Formula I and Formula II:

wherein the variables EG, EG1, SP1, SP2, SP3, Ar and BG are as definedherein. In another embodiment, the application discloses a method forforming a coating on a surface of a substrate using the surface bindingcompound of the Formula I or II.

DETAILED DESCRIPTION OF THE INVENTION

In one embodiment, the present application discloses novel, structurallydefined, small molecule compounds as primers and adhesives for medical,dental and electronic applications. In one embodiment, the presentapplication discloses primers, including polyhydroxy aromatic compounds,such as tri-, tetra- and penta-hydroxy benzene, indole and imidazolemoieties and their derivatives, that may form bonds, such as hydrogenbonds and/or attach via chelation or a coordination on to a materialsurface, such as a mineral, metal or oxide-containing surface of amaterial. In one aspect, these head moities adhere/adsorb on to mineraland metal oxide surfaces and generate secondary surfaces to interact (orcrosslink) with bulk adhesive, resins or copolymer surfaces to enhanceperformance of bonding between minerals, metals and metal oxidecontaining surfaces. Non-exclusive material surfaces include adhesives,cements, resins, paints, inks, proteins etc. . . . .

Some embodiments of the present invention are discussed in detail below.In describing embodiments, specific terminology is employed for the sakeof clarity. However, the present application is not intended to belimited to the specific terminology so selected. A person skilled in therelevant art will recognize that other equivalent components can beemployed and other methods developed without departing from the broadconcepts of the current invention. All references cited anywhere in thisspecification are incorporated by reference into this disclosure.

In one embodiment, the application discloses compounds comprising anaromatic group-containing surface primer. In one aspect, the surfaceprimer contains an aromatic group. In another aspect, the compoundcomprises an aromatic group attached to a functional end group through aspacer group. In another embodiment, the compounds undergo self-assemblyonto a substrate, such as a mineral substrate or a metal oxidesubstrate. When applied to an oxide containing surface, the aromaticgroup of the compound may self-assemble and form a bond, such as ahydrogen bond, onto the oxide containing surface.

In another aspect, the compound forms a chelate or a coordinationcomplex on to the metal surface of a substrate. The functional end groupof the compound can form a secondary surface layer to interact/crosslinkwith bulk materials chemically, physico-chemically or physically viacross-linking, hydrogen bonding, oxide-metal coordination, electrostaticor hydrophobic interaction. A secondary surface can optionally beapplied onto the primer.

According to the present process, the secondary layer may be tunable bymodifying the compound, including the functional end group of thearomatic group.

In one embodiment, the present application discloses a surface bindingcompound of the Formula I:

wherein:

each a is independently 1, 2, 3, 4 or 5;

m is 1, 2 or 3; n is 1, 2 or 3; i is 1, 2 or 3

each EG is an end group independently selected from the group consistingof a C₁₋₁₂alkyl, CH₂═CH—, CH₂═C(C₁₋₃alkyl)-, CH₂═CHC(O)—,CH₂═C(C₁₋₃alkyl)C(O)—, CH₂═CHC(O)O—, CH₂═C(C₁₋₃alkyl)C(O)O—,CH₂═C(phenyl)C(O)O—, CH₂═C(C₁₋₃alkyl)S(O)_(n)O—, isocyanate, epoxy,oxetanyl, styrenyl, vinyl ether, (OH)SiR₂—, (OH)SiR₂(O)—, —Ar—(BG)_(a),aryl, heteroaryl, —N⁺R₁R₂R₃, —PO₄ ⁻, —N⁺R₁R₂R₃X⁻, —PO₄ ⁻Y⁺, —SO₄ ⁻Y⁺,wherein each R, R₁, R₂ and R₃ is independently H and C₁₋₃alkyl, X⁻ isCl⁻, Br⁻ and I⁻ and Y⁺ is H⁺ or N⁺R₁R₂R₃;

each of SP1, SP2 and SP3 is a spacer independently selected from thegroup consisting of —O—, —C(O)—, —S—, —S(O)—, —S(O)₂—, —N—, —NH—,—NCH₃—, —C—, —CH—, —(CH₂)_(q)—, —(CH(OH))_(q)—, —(CH₂CH(OH)CH₂)_(q)—,—(C(CH₃)₂)_(q)—, —(CH(CH₃))_(q)—, —NH(CH₂)₂NH—, —OC(O)—, —CO₂—,—NHCH₂CH₂C(O)—, —OCH₂CH₂C(O)—, —C(O)CH₂CH₂C(O)—, —C(O)NHCH₂CH₂NH—,—NHCH₂C(O)—, —NHC(O)—, —C(O)N—, —NC(O)—, —C(O)NH—, —NCH₃C(O)—,—C(O)NCH₃—, —(CH₂CH₂O)_(p)—, —(CH₂CH₂O)_(p)CH₂CH₂—,—CH₂CH₂—(CH₂CH₂O)_(p)—, —OCH(CH₂O—)₂—, —(CH₂)_(q)—N⁺R₁R₂—,—(CH₂)_(q)—PO₄ ⁻, —N⁺R₁R₂—, —PO₄ ⁻—, —(CH₂)_(q)—N⁺R₁R₂—X⁻—,—(CH₂)_(q)—PO₄ ⁻Y⁺—, —N⁺R₁R₂—X⁻—, —PO₄ ⁻Y⁺—, —SO₄ ⁻Y⁺—,—O—PO⁻(O)O—(CH₂)₂₋₄—N⁺(R₁R₂)—, -(AA)_(r)-, aryl, cyclopentanyl,cyclohexanyl, unsubstituted phenylenyl and phenylenyl substituted by 1or 2 substituents selected from the group consisting of halo, CF₃—,CF₃O—, CH₃O—, —C(O)OH, —C(O)OC₁₋₃alkyl, —C(O)CH₃, —CN, —NH₂, —OH,—NHCH₃, —N(CH₃)₂ and C₁₋₃alkyl, wherein each AA is independently anamino acid, p is 1-6, q is 1-6 and r is 1-6;

Ar is an aryl or heteroaryl group;

each BG is a bonding group independently selected from the groupconsisting of —OH, —SiR₂OH, —COOH, —SO₃H, —P(O)₃OH, —CONH₂, —CSNH₂,—CF₃, —CF₂CF₃, —OCF₃ and —OCF₂CF₃; provided that:

a) at least one of SP1, SP2 and SP3 is a spacer selected from the groupconsisting of A, A1, A2, B, C, F, G, H, H-1, I, I-1, J, J-1, K, K-1, L,L-1, M, M-1, N, O, P, Q and R:

wherein:

Z is selected from the group consisting of C, S, S(O), P(OH) and P(OR);

each E is independently selected from the group consisting of halo,CF₃—, CF₃O—, HO— and CH₃O—; and e is 0, 1, 2 or 3; and

b) when one of SP1, SP2 and SP3 is not a spacer selected from the groupconsisting of A, B, C, D, E, F, G, H, H-1, I, I-1, J, J-1, K, K-1, L,L-1, M, M-1, N, O, P, Q and R, then each of the groups

is independently selected from the group consisting of:

wherein: each Z is independently selected from the group consisting ofC, S, S(O), P(OH) and P(OR). In one variation of the compounds, Z is Cor S.

In another embodiment, there is provided a surface binding compound ofthe Formula II:

wherein: m is 1, 2 or 3; n is 1, 2 or 3; i is 1, 2 or 3;

each EG and EG1 is an end group independently selected from the groupconsisting of a C₁₋₁₂alkyl, CH₂═CH—, CH₂═C(C₁₋₃alkyl)-, CH₂═CHC(O)—,CH₂═C(C₁₋₃alkyl)C(O)—, CH₂═CHC(O)O—, CH₂═C(C₁₋₃alkyl)C(O)O—,CH₂═C(phenyl)C(O)O—, CH₂═C(C₁₋₃alkyl)S(O)_(n)O—, isocyanate, epoxy,oxetanyl, styrenyl, vinyl ether, (OH)SiR₂—, (OH)SiR₂(O)—, —Ar—(BG)_(a),aryl, heteroaryl, —N⁺R₁R₂R₃, —PO₄ ⁻, —N⁺R₁R₂R₃X⁻, —PO₄ ⁻Y⁺, —SO₄ ⁻Y⁺,wherein each R, R₁, R₂ and R₃ is independently H and C₁₋₃alkyl, X⁻ isCl⁻, Br⁻ and I⁻ and Y⁺ is H⁺ or N⁺R₁R₂R₃;

each of SP1, SP2 and SP3 is a spacer independently selected from thegroup consisting of —O—, —C(O)—, —S—, —S(O)—, —S(O)₂—, —N—, —NH—,—NCH₃—, —C—, —CH—, —(CH₂)_(q)—, —(CH(OH))_(q)—, —(CH₂CH(OH)CH₂)_(q)—,—(C(CH₃)₂)_(q)—, —(CH(CH₃))_(q)—, —NH(CH₂)₂NH—, —OC(O)—, —CO₂—,—NHCH₂CH₂C(O)—, —OCH₂CH₂C(O)—, —C(O)CH₂CH₂C(O)—, —C(O)NHCH₂CH₂NH—,—NHCH₂C(O)—, —NHC(O)—, —C(O)N—, —NC(O)—, —C(O)NH—, —NCH₃C(O)—,—C(O)NCH₃—, —(CH₂CH₂O)_(p)—, —(CH₂CH₂O)_(p)CH₂CH₂—,—CH₂CH₂—(CH₂CH₂O)_(p)—, —OCH(CH₂O—)₂—, —(CH₂)_(q)—N⁺R₁R₂—,—(CH₂)_(q)—PO₄ ⁻, —N⁺R₁R₂—, —PO₄ ⁻—, —(CH₂)_(q)—N⁺R₁R₂—X⁻—,—(CH₂)_(q)—PO₄ ⁻Y⁺—, —N⁺R₁R₂—X⁻—, —PO₄ ⁻Y⁺—, —SO₄ ⁻Y⁺—,—O—PO⁻(O)O—(CH₂)₂₋₄—N⁺(R₁R₂)—, -(AA)_(r)-, aryl, cyclopentanyl,cyclohexanyl, unsubstituted phenylenyl and phenylenyl substituted by 1or 2 substituents selected from the group consisting of halo, CF₃—,CF₃O—, CH₃O—, —C(O)OH, —C(O)OC₁₋₃alkyl, —C(O)CH₃, —CN, —NH₂, —OH,—NHCH₃, —N(CH₃)₂ and C₁₋₃alkyl, wherein each AA is independently anamino acid, p is 1-6, q is 1-6 and r is 1-6;

provided that at least one of SP1, SP2 and SP3 is a spacer selected fromthe group consisting of A, B, C, D, E, F, G, H, H-1, I, I-1, J, J-1, K,K-1, L, L-1, M, M-1, N, O, P, Q and R:

wherein: Z is selected from the group consisting of C, S, S(O), P(OH)and P(OR); each E is independently selected from the group consisting ofhalo, CF₃—, CF₃O—, HO— and CH₃O—; and e is 0, 1, 2 or 3; and providedthat when EG and EG1 are both CH₂═C(CH₃)C(O)O—CH₂CH₂)OC(O)— orCH₂═C(CH₃)C(O)NH—(CH₂CH₂)OC(O)—, then the spacer is not

As provided herein and used conventionally in the art for the compoundsof Formula I or II, the —Ar-BG group may be referred to as the headgroup, and the -EG group may be referred to as the tail group of theself-assembled layer or self assembled monolayer (SAM). As used herein,the formation of SAMs refers to the spontaneous formation of organicassemblies of the compound of the Formula I or II on a surface by theadsorption of compounds from the solution comprising the compounds by aprocess of synergistic intermolecular and/or intramolecularinteractions. In another variation, the compound comprises of theformulae IIa, IIb, IIc, IId, IIe, IIf, IIg and IIh:

wherein i, R, SP1 and SP3 are as defined in Formula II.

In one variation of the compound of the Formula I, —Ar-BG is not a3,4-dihydroxyphenyl group. As defined herein, when each of SP1, SP2 andSP3 is independently a —N—, —C—, —C(O)N— or —NC(O)— group, thesetrivalent and tetravalent groups may be substituted and may formbranched structures, leading up to various arrays, as represented by,e.g., dendrimeric species. For example, when SP1 is —N— or —C—, thecompound of the Formula I (or Formula II) may form a branched structureat the nitrogen atom or carbon atom, respectively, as shown:

Similarly, branched structures may also be formed with SP1 and SP2, SP2and SP3, or a combination of SP1, SP2 and SP3.

The dendrimer-like or branched structures disclosed above may also besimilarly applicable for the compound of the Formula II. As providedherein for example, a spacer designated or bonded as —C(O)NH— alsoinclude the reversible (inverted) spacer that is bonded as —NHC(O)—.

In another variation, the SP1, SP2 and SP3 groups may be independentlyselected from:

In one aspect of the surface binding compound of Formula II, each EG andEG1 is independently selected from the group consisting of a C₁₋₁₂alkyl,CH₂═CHC(O)O—, CH₂═C(C₁₋₃alkyl)C(O)O—, CH₂═C(phenyl)C(O)O—, isocyanate,epoxy, oxetanyl, styrenyl, vinyl ether, —Ar—(BG)_(a), phenyl andnaphthyl. In one variation, each EG and EG1 is independently selectedfrom the group consisting of a CH₂═CHC(O)O— and CH₂═C(C₁₋₃alkyl)C(O)O—.In one variation, each EG and EG1 is independently —N⁺(CH₃)(CH₂OH)₂,—N⁺(CH₃)₂(CH₂OH) and —N⁺(CH₂OH)₃. In another variation, EG and EG1 arethe same.

In one variation, each EG and EG1 is independently selected from thegroup consisting of C₁alkyl, C₃alkyl, C₆alkyl, C₁₂alkyl,CH₂═C(CH₃)C(O)O—, CH₂═C(CH₂CH₃)C(O)O—, CH₂═C(C₁₋₃alkyl)S(O)₂O— andCH₂═C(CH₂CH₂CH₃)C(O)O—. In another variation, each EG is independently aC₆alkyl, C₃alkyl or a C₁alkyl or —CH₃. In another variation, each EG andEG1 is independently selected from the group consisting of phenyl ornaphthyl each optionally substituted by one or two functional groupsselected from the group consisting of halo (F, Cl, Br, I), CF₃—, CF₃O—,CH₃O—, —C(O)OH, —C(O)OC₁₋₃alkyl, —C(O)CH₃, —CN, —NH₂, —OH, —NHCH₃,—N(CH₃)₂ and C₁₋₃alkyl.

In certain aspects, the EG and EG1, referred to as the head or tail willdepend on the nature of the functional group and conditions that allowEG or EG1 to bind first or second, respectively. For example, if EG andEG1 are different, and EG is an acrylate group that bonds to a surfacefirst, the EG may be referred to as the head, and EG1 as the tail. Inone aspect, GE and EG1 may independently comprise of a polymerizablegroup, such as a mono-, di- or poly-acrylates and methacrylates (e.g.,methyl acrylate, methyl methacrylate, ethyl(methyl)acrylate,isopropyl(methyl)acrylate, n-hexyl(methyl)acrylate,stearyl(methyl)acrylate, allyl(methyl)acrylate, glyceroldi(methyl)acrylate, glycerol tri(methyl)acrylate, ethyleneglycoldi(methyl)acrylate, diethyleneglycol di(methyl)acrylate,triethyleneglycol di(methyl)acrylate, 1,3-propanediol diacrylate,1,3-propanediol dimethacrylate, trimethylolpropane tri(methyl)acrylate,1,2,4-butanetriol tri(methyl)acrylate and 1,4-cyclohexanedioldi(methyl)acrylate.

In another aspect of the surface binding compound, each EG and EG1 isindependently selected from the group consisting of imidazolyl, indolyl,—N⁺R₁R₂R₃, —PO₄ ⁻, —N⁺R₁R₂R₃X⁻, —PO₄ ⁻Y⁺, —SO₄ ⁻Y⁺, wherein each R₁, R₂and R₃ is independently H and C₁₋₃alkyl, X⁻ is Cl⁻, Br⁻ and I⁻ and Y⁺ isH⁺ or —N⁺R₁R₂R₃. In one variation, each R, R₁, R₂ and R₃ isindependently H and C₁₋₃alkyl optionally substituted with —OH, —SH or—NH₂.

In another aspect, each of SP1, SP2 and SP3 is a spacer independentlyselected from the group consisting of —(CH₂)_(q)—, —NH(CH₂)₂NH—,—NHCH₂CH₂C(O)—, —C(O)NHCH₂CH₂NH—, —NHCH₂C(O)—, —NHC(O)—, —C(O)N—,—NC(O)—, —C(O)NH—, —NCH₃C(O)—, —C(O)NCH₃—, —(CH₂CH₂O)_(p)—,—(CH₂CH₂O)_(p)CH₂CH₂—, —CH₂CH₂—(CH₂CH₂O)_(p)— and —OCH(CH₂O—)₂—.

In another aspect, each of SP1, SP2 and SP3 is a spacer independentlyselected from the group consisting of —N⁺R₁R₂—, —PO₄ ⁻—, —N⁺R₁R₂X⁻—,—PO₄ ⁻Y⁺—, —SO₄ ⁻Y⁺—, —(CH₂)_(q)—N⁺R₁R₂—, —(CH₂)_(q)—PO₄ ⁻,—(CH₂)_(q)—N⁺R₁R₂—X⁻—, —(CH₂)_(q)—PO₄ ⁻Y⁺— and—O—PO⁻(O)O—(CH₂)₂₋₄—N⁺(R₁R₂)—.

In yet another aspect of the surface binding compound, each of SP1, SP2and SP3 is independently selected from —CH₂CH₂—C(O)NHCH₂CH₂NH—C(O)NCH₃—,—NHC(O)—(CH₂CH₂O)_(p)—(CH₂)_(q)—,—(CH₂CH₂O)_(p)CH₂CH₂—C(O)NCH₃—(CH₂CH₂O)_(p)CH₂CH₂—,—NHCH₂CH₂C(O)—(CH₂)_(q)—PO₄ ⁻, —PO₄ ⁻—(CH₂)_(q)—N⁺R₁R₂X⁻—,—(CH₂CH₂O)_(p)—(CH₂)_(q)—PO₄ ⁻, —N⁺R₁R₂X⁻—(CH₂)_(q)—PO₄ ⁻ and —PO₄⁻—(CH₂CH₂O)_(p)—N⁺R₁R₂X⁻—.

In another aspect of the surface binding compound, each BG is a bondinggroup independently selected from the group consisting of —OH, —SiR₂OH,—COOH, —SO₃H, —P(O)₃OH, —CONH₂ and —CSNH₂. In yet another aspect of thesurface binding compound, —SP3- is —CH₂— and Ar—(BG)_(a) is selectedfrom the group consisting of 2,3-dihydroxyphenyl, 3,4-dihydroxyphenyl,2,3,4-trihydroxyphenyl, 3,4,5-trihydroxyphenyl,2,3,4,5-tetrahydroxyphenyl, 2,3,4,5,6-pentahydroxyphenyl,2,3-dicarboxyphenyl, 2,3,4-tricarboxyphenyl, 3,4,5-tricarboxylphenyl,2,3,4,5-tetracarboxyphenyl, 2,3,4,5,6-pentacarboxyphenyl,2,3-disiloxyphenyl, 2,3,4-trisiloxyphenyl, 3,4,5-trisiloxyphenyl,2,3,4,5-tetrasiloxyphenyl and 2,3,4,5,6-pentasiloxyphenyl.

In another aspect of the surface binding compound, each EG and EG1 isindependently an aryl group selected from the group consisting of:

wherein the aryl group is optionally substituted by 1 or 2 substituentsselected from halo, CF₃—, CF₃O—, CH₃O—, —C(O)OH, —C(O)OC₁₋₃alkyl,—C(O)CH₃, —CN, —NH₂, —OH, —SiR₂OH, —NHCH₃, —N(CH₃)₂ and C₁₋₃alkyl.

In one variation, each EG and EG1 is independently a cationic, anionic,zwitterionic, polar and non-polar group. In another variation, m is 2 or3, and the acrylate is a di-acrylate or a tri-acrylate. In onevariation, m is 1 and n is 1. In one variation, p is 1, 2, 3, 4, 5 or 6,q is 1, 2, 3, 4, 5 or 6 and r is 1, 2, 3, 4, 5 or 6.

In one particular variation, all of the BG groups on Ar are all adjacentto one another. In one embodiment, each BG is —OH. In one variation, BGis —OH, —COOH and —OH. In another variation, BG is —OH, —SiR₂OH or —OH,or a combination thereof. In one variation, R is H. In another variationof the compound of the Formula I and Formula II, the molecular weight isless than 2 kDa, less than 1 kDa or less than 0.5 kDa.

In another embodiment, there is provided a method for forming a coatingon a surface of a substrate, the method comprises:

1) washing the surface of the substrate with a first solvent;

2) contacting the surface binding compound of the Formula I, optionallyin a second solvent, to the surface:

wherein: each a is independently 1, 2, 3, 4 or 5; m is 1, 2 or 3; n is1, 2 or 3; i is 1, 2 or 3;

each EG is an end group independently selected from the group consistingof a C₁₋₁₂alkyl, CH₂═CH—, CH₂═C(C₁₋₃alkyl)-, CH₂═CHC(O)—,CH₂═C(C₁₋₃alkyl)C(O)—, CH₂═CHC(O)O—, CH₂═C(C₁₋₃alkyl)C(O)O—,CH₂═C(phenyl)C(O)O—, CH₂═C(C₁₋₃alkyl)S(O)_(n)O—, isocyanate, epoxy,oxetanyl, styrenyl, vinyl ether, (OH)SiR₂—, (OH)SiR₂(O)—, —Ar—(BG)_(a),aryl, heteroaryl, —N⁺R₁R₂R₃, —PO₄ ⁻, —N⁺R₁R₂R₃X⁻, —PO₄ ⁻Y⁺, —SO₄ ⁻Y⁺,wherein each R, R₁, R₂ and R₃ is independently H and C₁₋₃alkyl, X⁻ isCl⁻, Br⁻ and I⁻ and Y⁺ is H⁺ or N⁺R₁R₂R₃;

each of SP1, SP2 and SP3 is a spacer independently selected from thegroup consisting of —O—, —C(O)—, —S—, —S(O)—, —S(O)₂—, —N—, —NH—,—NCH₃—, —C—, —CH—, —(CH₂)_(q)—, —(CH(OH))_(q)—, —(CH₂CH(OH)CH₂)_(q)—,—(C(CH₃)₂)_(q)—, —(CH(CH₃))_(q)—, —NH(CH₂)₂NH—, —OC(O)—, —CO₂—,—NHCH₂CH₂C(O)—, —OCH₂CH₂C(O)—, —C(O)CH₂CH₂C(O)—, —C(O)NHCH₂CH₂NH—,—NHCH₂C(O)—, —NHC(O)—, —C(O)N—, —NC(O)—, —C(O)NH—, —NCH₃C(O)—,—C(O)NCH₃—, —(CH₂CH₂O)_(p)—, —(CH₂CH₂O)_(p)CH₂CH₂—,—CH₂CH₂—(CH₂CH₂O)_(p)—, —OCH(CH₂O—)₂—, —(CH₂)_(q)—N⁺R₁R₂—,—(CH₂)_(q)—PO₄ ⁻, —N⁺R₁R₂—, —PO₄ ⁻—, —(CH₂)_(q)—N⁺R₁R₂—X⁻—,—(CH₂)_(q)—PO₄ ⁻Y⁺—, —N⁺R₁R₂—X⁻—, —PO₄ ⁻Y⁺—, —SO₄ ⁻Y⁺—,—O—PO⁻(O)O—(CH₂)₂₋₄—N⁺(R₁R₂)—, -(AA)_(r)-, aryl, cyclopentanyl,cyclohexanyl, unsubstituted phenylenyl and phenylenyl substituted by 1or 2 substituents selected from the group consisting of halo, CF₃—,CF₃O—, CH₃O—, —C(O)OH, —C(O)OC₁₋₃alkyl, —C(O)CH₃, —CN, —NH₂, —OH,—NHCH₃, —N(CH₃)₂ and C₁₋₃alkyl, wherein each AA is independently anamino acid, p is 1-6, q is 1-6 and r is 1-6;

Ar is an aryl or heteroaryl group;

each BG is a bonding group independently selected from the groupconsisting of —OH, —SiR₂OH, —COOH, —SO₃H, —P(O)₃OH, —CONH₂, —CSNH₂,—CF₃, —CF₂CF₃, —OCF₃ and —OCF₂CF₃; provided that:

a) at least one of SP1, SP2 and SP3 is a spacer selected from the groupconsisting of A, A1, A2, B, C, D, E, F, G, H, H-1, I, I-1, J, J-1, K,K-1, L, L-1, M, M-1, N, O, P, Q and R:

wherein: Z is selected from the group consisting of C, S, S(O), P(OH)and P(OR);

each E is independently selected from the group consisting of halo,CF₃—, CF₃O—, HO— and CH₃O—; and e is 0, 1, 2 or 3; and

b) when one of SP1, SP2 and SP3 is not a spacer selected from the groupconsisting of A, B, C, D, E, F, G, H, H-1, I, I-1, J, J-1, K, K-1, L,L-1, M, M-1, N, O, P, Q and R, then each of the group

is independently selected from the group consisting of:

wherein: each Z is selected from the group consisting of C, S, S(O),P(OH) and P(OR);

3) for a period of time for the compound of the Formula I to form alayer on the surface of the substrate; and optionally, 4) washing theexcess compound of the Formula I from the surface of the substrate witha sufficient amount of a third solvent to remove excess compound fromthe surface.

In one variation of the method, the compound of the Formula I or IIforms a SAM. In one variation of the method, the compound used is acompound of the Formula I, or a mixture of the compound of the Formula Ito provide the desired improved mechanical or electronic properties ofthe substrate. In another variation, the first solvent is water, anorganic solvent or a mixture of water and the organic solvent. In aparticular variation, the organic solvent is selected from the groupconsisting of methanol, ethanol, propanol, isopropanol, acetone,methylethyl ketone (2-butanone), hexanes, cyclohexane, heptane, toluene,xylenes, THF, Me-THF and N-methylpyrrolidone, and mixtures thereof. Inanother variation, the first, second and third solvents are the same orare different, and are selected from the group consisting of water,methanol, ethanol, a mixture of water and methanol, a mixture of waterand ethanol or a combination thereof. In another variation, the firstsolvent is different than the second and the third solvent.

In another aspect of the method, each EG and EG1 is independentlyselected from the group consisting of a C₁₋₁₂alkyl, CH₂═CHC(O)O—,CH₂═C(C₁₋₃alkyl)C(O)O—, CH₂═C(phenyl)C(O)O—, isocyanate, epoxy,oxetanyl, styrenyl, vinyl ether, —Ar—(BG)_(a), phenyl and naphthyl.

In another aspect of the method, each EG and EG1 is independentlyselected from the group consisting of imidazolyl, indolyl, —N⁺R₁R₂R₃,—PO₄ ⁻, —N⁺R₁R₂R₃X⁻, —PO₄ ⁻Y⁺, —SO₄ ⁻Y⁺, wherein each R₁, R₂ and R₃ isindependently H and C₁₋₃alkyl, X⁻ is Cl⁻, Br⁻ and I⁻ and Y⁺ is H⁺ or—N⁺R₁R₂R₃. In one variation, the imidazolyl is an imidazolinium, and theindolyl is an indolinium and the counterion is a halide, sulfonate orphosphate.

In yet another aspect of the method, each of SP1, SP2 and SP3 is aspacer independently selected from the group consisting of —(CH₂)_(q)—,—NH(CH₂)₂NH—, —NHCH₂CH₂C(O)—, —C(O)NHCH₂CH₂NH—, —NHCH₂C(O)—, —NHC(O)—,—C(O)N—, —NC(O)—, —C(O)NH—, —NCH₃C(O)—, —C(O)NCH₃—, —(CH₂CH₂O)_(p)—,—(CH₂CH₂O)_(p)CH₂CH₂—, —CH₂CH₂—(CH₂CH₂O)_(p)— and —OCH(CH₂O)₂—. In yetanother aspect of the method, each of SP1, SP2 and SP3 is a spacerindependently selected from the group consisting of —N⁺R₁R₂—, —PO₄ ⁻—,—N⁺R₁R₂X⁻—, —PO₄ ⁻Y⁺—, —SO₄ ⁻Y⁺—, —(CH₂)_(q)—N⁺R₁R₂—, —(CH₂)_(q)—PO₄ ⁻,—(CH₂)_(q)—N⁺R₁R₂—X⁻—, —(CH₂)_(q)—PO₄ ⁻Y⁺— and —O—PO⁻(O)O—(CH₂)₂₋₄—N⁺(R₁R₂)—.

In another aspect of the method, each SP1, SP2 and SP3 is a spacerindependently selected from the group consisting of—CH₂CH₂—C(O)NHCH₂CH₂NH—C(O)NCH₃—, —NHC(O)—(CH₂CH₂O)_(p)—(CH₂)_(q)—,—(CH₂CH₂O)_(p)CH₂CH₂—C(O)NCH₃—(CH₂CH₂O)_(p)CH₂CH₂—,—NHCH₂CH₂C(O)—(CH₂)_(q)—PO₄ ⁻, —PO₄ ⁻—(CH₂)_(q)—N⁺R₁R₂X⁻—,—(CH₂CH₂O)_(p)—(CH₂)_(q)—PO₄ ⁻, —N⁺R₁R₂X⁻—(CH₂)_(q)—PO₄ ⁻ and —PO₄⁻—(CH₂CH₂O)_(p)—N⁺R₁R₂X⁻—.

In another aspect of the method, Ar is an aryl group selected from:

In another aspect of the method, each BG is a bonding groupindependently selected from the group consisting of —OH, —SiR₂OH, —COOH,—SO₃H, —P(O)₃OH, —CONH₂ and —CSNH₂.

In another aspect of the method, —SP3- is —CH₂— and Ar—(BG)_(a) isselected from the group consisting of 2,3-dihydroxyphenyl,3,4-dihydroxyphenyl, 2,3,4-trihydroxyphenyl, 3,4,5-trihydroxyphenyl,2,3,4,5-tetrahydroxyphenyl, 2,3,4,5,6-pentahydroxyphenyl,2,3-dicarboxyphenyl, 2,3,4-tricarboxyphenyl, 3,4,5-tricarboxylphenyl,2,3,4,5-tetracarboxyphenyl, 2,3,4,5,6-pentacarboxyphenyl,2,3-disiloxyphenyl, 2,3,4-trisiloxyphenyl, 3,4,5-trisiloxyphenyl,2,3,4,5-tetrasiloxyphenyl and 2,3,4,5,6-pentasiloxyphenyl.

In another aspect of the method, the coating is formed by aself-assembly of the compound of the Formula I or Formula II onto thesurface. In yet another aspect of the method, the self-assembled layeris about 0.1 nm to 20 nm, about 0.1 to 15 nm, 0.1 to 10 nm or about 0.1to 5 nm.

In another aspect of the method, the coating is a material selected froman adhesive or a primer. In another aspect of the method, the substrateis selected from the group consisting of an oxide, a metal, a metaloxide and a mineral. In another aspect of the method, the substrate isselected from the group consisting of mica, silicon, glass, calcium,enamel, bone, steel, tooth enamel, tooth dentin, hydroxylapatite, kaolinand zirconia. In another aspect, the metal, metal oxide or oxide isselected from the group consisting of silicate mineral, silica, kaolin,zirconia, aluminum, copper, chrome, chrome-cobalt, titanium, zinc, tin,indium-tin and calcium oxide.

In yet another aspect of the method, the adhesive is formed bycontacting the tail end of the self-assembled layer comprising the -EGgroups of the substrate that is the first substrate, with the tail endof a second substrate comprising a surface binding compound of theFormula I, whereby the tail end of the compound of the Formula I of thefirst substrate binds with the tail end of the compound of the Formula Iof the second substrate. For the compound of the Formula II, forexample, the adhesive is formed by contacting one end (or the head) ofthe self-assembled layer comprising the EG or EG1 groups of thesubstrate that is the first substrate, with the other end (the EG or EG1groups) of a second substrate comprising a surface binding compound ofthe Formula II, whereby the EG end of the compound of the Formula II ofthe first substrate binds with the EG1 end of the compound of theFormula II of the second substrate. In yet another aspect of the method,the adhesive forms an adhesive layer for dental application, medicalimplants and orthopedic application. In another aspect, the metal oxideis selected from the group consisting of aluminum oxide, copper oxide,chrome, chrome-cobalt, titanium oxide, zinc oxide, tin oxide andindium-tin-oxide (ITO).

In another aspect of the above method, the substrate is selected fromthe group consisting of polytetrafluoroethylene (PTFE), silicon, siliconwafer, polyvinyl fluoride (PVF), natural rubber (CR), polypropylene(PP), polyethylene (PE), polymethyl methacrylate, acryl (PMMA), epoxy(EP), polyoxymethylene, acetal (POM), polystyrene (PS), polyvinylchloride (PVC), vinylidene chloride (VC), polyester (PET), polyimide(PI), polyarylsulfone (PAS), phenolic resin, polyurethane (PUR),polyamide 6 (PA 6), polycarbonate (PC), lead (Pb), aluminum (Al), copper(Cu), chromium (Cr), iron (Fe) and stainless steel (SS).

In another aspect, there is provided a method for bonding a dentalobject on a surface of a tooth comprising: a) preparing the toothsurface for bonding; b) applying a photocleavable adhesive or a mixtureof adhesives to the tooth surface; c) contacting the photocleavableadhesive or mixture of adhesives with a dental adhesive to form abonding mixture; d) contacting the dental object with the combinedadhesive mixture to secure the dental object onto the surface of thetooth; and e) applying a source of light to the combined adhesivemixture for a sufficient period of time to cure the combined adhesivemixture and secure the dental object onto the tooth surface; wherein thephotocleavable adhesive or mixture of adhesives comprise of the surfacebinding compound or mixtures thereof, as described herein, or a compoundof the formulae 89 to 96, or mixtures thereof. In another aspect, themethod further comprises f) allowing the dental object to remain on thetooth surface for a sufficient period of time to bond to the toothsurface and remain for a desired purpose; and g) exposing the combinedadhesive mixture with a UV radiation or IR radiation for a sufficientperiod of time, optionally with physical agitation of the dental objectand or the tooth for a sufficient period of time, to debond or removethe dental object from the surface.

In another aspect of the method, the coating is formed by aself-assembly of the compound of the Formula I or Formula II onto thesurface. In one variation, the self-assembled layer is a self-assembledmonolayer (SAM). In one variation, the self-assembled layer forms atless than 40° C., less than 30° C. or at about RT. In another variation,the self-assembled monolayer forms in less than about 60 min., less than45 min., less than 30 min. or less than about 15 min.

In another aspect of the method, the coating is a material selected froman adhesive or a primer. In yet another aspect of the above method, thesubstrate is selected from the group consisting of an oxide, a metal, ametal oxide and a mineral. In another aspect of the method, thesubstrate is selected from the group consisting of mica, silicon, glass,calcium, enamel, bone, steel, tooth enamel, tooth dentin,hydroxylapatite, kaolin and zirconia. In another aspect of the method,the metal, metal oxide or oxide is selected from the group consisting ofsilicate mineral, silica, kaolin, zirconia, aluminum, copper, chrome,chrome-cobalt, titanium, zinc, tin, indium-tin and calcium oxide.

In another embodiment, there is provided a method for bonding a dentalobject on a surface of a tooth comprising: a) preparing the toothsurface for bonding; b) applying a photocleavable adhesive or a mixtureof adhesives to the tooth surface; c) contacting the photocleavableadhesive or mixture of adhesives with a dental adhesive to form abonding mixture; d) contacting the dental object with the combinedadhesive mixture to secure the dental object onto the surface of thetooth; and e) applying a source of light to the combined adhesivemixture for a sufficient period of time to cure the combined adhesivemixture and secure the dental object onto the tooth surface; wherein thephotocleavable adhesive or mixture of adhesives comprise of the surfacebinding compound or mixtures thereof, as disclosed herein. In onevariation, the mixture of adhesives comprises of photocleavableadhesive, a mixture of photocleavable adhesives, and a mixture ofphotocleavable and non-photocleavable adhesives. In one variation, thephotocleavable adhesive is selected from a compound of the formulae 1 to45 or a mixture thereof. In one variation, the photocleavable adhesiveis selected from the compound of the formulae 89 to 96, or a mixturethereof. In another variation, the non-photocleavable adhesive compriseof the compound of the formulae 63 to 89, or mixtures thereof. In onevariation, the source of light for curing the bonding mixture is visiblelight, such as an LED blue light. In another variation, the dentaladhesive is a resin cement or a commercially available dental adhesiveor dental cement. In another variation, the dental adhesive is Bis-GMAand TEGDMA, and DMAEMA and an initiator, such as CQ. In another aspect,the method further comprises: f) allowing the dental object to remain onthe tooth surface for a sufficient period of time to bond to the toothsurface and remain for a desired purpose; and g) exposing the combinedadhesive mixture with a UV radiation or IR radiation for a sufficientperiod of time, optionally with physical agitation of the dental objectand/or the tooth for a sufficient period of time, to debond or removethe dental object from the surface.

In another aspect of the method, the adhesive is formed by contactingthe tail end of the self-assembled layer comprising the -EG groups ofthe substrate that is the first substrate, with the tail end of a secondsubstrate comprising a surface binding compound of the Formula I,whereby the tail end of the compound of the Formula I of the firstsubstrate binds with the tail end of the compound of the Formula I ofthe second substrate. In one variation, the compound of the Formula I inthe first substrate is the same or different than the compound of theFormula I in the second substrate. Similarly, in one variation, thecompound of the Formula II in the first substrate is the same ordifferent than the compound of the Formula II in the second substrate.In another variation, the head end of the compound of the Formula I, orthe EG or EG1 group of the compound of the Formula II, binds with thesurface of the substrate via hydrogen bonds, chelation, metal-oxygencoordination bond or via a covalent bond.

In another aspect of the method, the adhesive forms an adhesive layerfor dental application, medical implants and orthopedic application. Inone variation, the adhesive layer may be used as an enamel adhesive orcement or a bone adhesive or cement. For dental applications, theadhesive layer may be used as a filling, a general adhesive, a cavityliner, a dental cement, a coating composition with or without filler, aroot canal filler or sealant with or without filler or a combinationthereof. In one variation the adhesive layer may be a self-adhesivecomposition or a photo-curable composition. In one variation, thecompounds of Formula I and II may be cross-linking agents.

Methods of forming a SAM coating on a surface of a substrate are knownin the art. The SAM or SAM coating that forms the EG group or the —Ar-BGgroup may include organosilanes or other silane molecules. In onevariation, the SAM coating is a chlorosilane, such as a trichlorosilaneor a methoxysilane. Tricholorosilanes of a SAM as provided herein may beselected from a n-decyl-trichlorosilane (DTS), an-dodecyl-trichlorosilane, a perfluorodecyl-trichlorosilane (FDTS) or an-octadecyltrichlorosilane. As provided herein, a SAM may include adimethylaminosilanes and alklysilanes, and alkyltricholorosilane oralkyltrimethoxysilane. In one variation, the SAM comprises siloxanessuch as hexamethyldisilazane (HMDS).

In one variation, the coating is a self-assembled layer of the compound.In another variation, the surface is a gate dielectric surface forelectronic devices, such as an organic field-effect transistor. Inanother variation, the self-assembled monolayer is ordered anddefect-free. In one aspect of the SAMs of the present application, atleast 30%, 40%, 50%, 60%, 70%, 80%, 90% or more than 95% of thecompounds that adsorb to the surface bond to the surface of thesubstrate. In another variation, the high bonding layer provideswell-defined, uniform and reproducible layers, such as monolayers, thatare bonded to the surface of the substrate. The substantially orderedand defect-free layers may be characterized and confirmed using AtomicForce Microscope (AFM), X-Ray Scattering or a combination thereof, asknown in the art.

In another variation of the method, the self-assembled layer is asurface modifier used for anode binders, electro circuits, field effecttransistors (FET; with range value of 20-50 cm²V⁻¹s⁻¹), semiconductors,nanosensing devices, organic solar cells, opto-electronic devices,hetero junctions and electron tunneling junctions. In one variation ofthe above, the self-assembled layer is a self-assembled monolayer (SAM).

In another variation, the compound forms a SAM in less than about 60minutes, less than 30 minutes, less than 10 minutes, less than 5minutes, less than about 2 minutes or less than about 1 minute aftercontacting with the surface of the substrate. In one variation of themethod, the compound forms a substantially smooth, uniform anddefect-free SAM.

In one variation of the method, the SAM is a surface modifier thatproduces low contact angles (θ) of less than 20°, less than 15°, than 13or less than 11 for a chlorobenzene droplet.

In another variation, the SAM surface modifiers are omniphilic with <30°contact angle for water droplets. In one variation, the SAM forms amonolayer of about 0.1 nm to 50 nm, 0.1 nm to 40 nm, 0.1 nm to 30 nm,0.1 nm to 20 nm or about 0.1 nm to 10 nm. In another variation, the SAMforms a monolayer of less than about 5 nm, less than 4 nm, less than 3nm or less than 2 nm.

In another variation of the method, the method further comprises:providing a layer of organic semiconducting material over the layer ofthe self-assembled layer or SAM. In according to one variation of theabove described methods, the method provides an improved organicthin-film transistor or other similar electronic devices. In one aspectof the method, the self-assembled layer may comprise a self-assembledmonolayer. The self-assembled layer may comprise a polymer layer. In onevariation of the method, the self-assembled layer may have a surfaceregion which is hydrophobic and/or oleophillic.

In one variation of the above adhesive, the bonding strength or theshear fracture strength is at least 15 kT, greater than 20 kT, greaterthan 25 kT, greater than 30 kT, greater than 35 kT, greater than 40 kT,greater than 45 kT or greater than 50 kT. In one variation of themethod, the adhesion is at least 30 mJ m⁻², 35 mJ m⁻², 40 mJ m⁻² or atleast 45 mJ m⁻².

In some embodiments, the compound of Formula I or Formula II may be usedas a primer or a coating. As disclosed herein, the compound of Formula Ior Formula II provides strong adhesion/adsorption and retains theability to interact or bond with a secondary layer. The compound mayadhere to a variety of surfaces and undergo self-assembly to form a thinprimer/coating/glue/adhesive layer. In some embodiments, theprimer/coating/glue/adhesive layer has a thickness from between 0.5 to50 nm.

In some embodiments as disclosed herein, the compound of Formula I orFormula II can be applied onto mineral or metal oxide surfaces, such asmica, silicon wafer, glass, bone, tooth enamel, tooth dentin,medical/dental implant, silica, kaolin, zirconia, aluminum, copper,chrome, chrome-cobalt, calcium, aluminum oxide, copper oxide, silicaoxide, titanium oxide, zinc oxide, calcium oxide, tin oxide, indium-tinoxide or hydroxylapatite.

In some embodiments, the deposited layer of the compound of Formula I orFormula II may be treated with an oxidizing agent, such as periodate. Inother embodiments, the layer may be treated with a base. Based on thehydroxyl-phenyl or phenolic groups that are similar to the molecule DOPA(3,4-dihydroxyphenylalanine), at low pH, the phenolic groups arestructurally favored over the corresponding keto- or quinone-likestructures (or tautomers), and accordingly, the phenolic forms providehigher bonding forces with the substrate. Accordingly, the keto- orquinone-like forms of the compound and their associated bonding forcesare provided at higher pH. Under substantially neutral pH conditions, astrong adhesive interaction of the compound to the substrate may beassociated with the interaction of the surfaces with the unoxidizedphenolic groups, and the weaker adhesive interaction of the compoundswith the surface may be associated with the corresponding oxidizedphenolic groups to the oxo- or quinone-type functionality. Accordingly,the surface bound materials may be treated with an oxidizing agent, ormay be treated with a base to adjust or modify the binding strength ofthe coating to the substrate. In some embodiments, deposition of thecompound upon the substrate, may be performed prior to treatment with anoxidizing agent. It is known that compounds possessing phenolic groupsmay be crosslinked under oxidative conditions to afford mixtures ofpolymeric phenols. Under conditions of neutral pH, or high pH, anadhesive interaction between the unoxidized phenolic groups of thecompound and the substrate results. Accordingly, the strong adhesiveinteraction between the phenolic compound and the substrate, willorganize the compound along the interface of the substrate. Once thesubstrate is deposited, oxidation may crosslink the phenolic groups ofthe compound along the interface between compound and substrate.Oxidation of the compound in solution, prior to deposition on substrate,may crosslink the phenolic groups differently, as a consequence ofdifferent chemical environments around the phenolic groups. Theresulting properties of the adhesive layer may be modified or adjustedby oxidizing the compound before or after depositing upon the substrate.

In some embodiments, the compound of Formula I or Formula II may be usedas a dental/bone adhesive, surface primers for dental/medical implants,surface primers for mineral fillers used for polymer compositesincluding dental and bone cements/adhesives/composites, or electronicdevices.

In some embodiments, the deposited layers of the present applicationcomprise a mixture of anionic and cationic groups, such as an anionic orcationic terminal group, provide anti-adsorption properties towardcertain compositions, such as proteins, and accordingly, provideeffective anti-fouling surfaces. As disclosed herein, the compoundscomprise, for example, a phosphate group and an ammonium salt, that formzwitterionic groups that are highly effective as anti-foulingcompositions and surfaces. In addition, the coating has the ability toresist the adsorption of bacteria, barnacle cypris larvae and algalzoospores, and accordingly prevent marine fouling of the surfaces. Inaddition, the surface materials are also effective as antibacterialsurfaces for different medical applications.

As disclosed herein, the anionic and cationic functional groups may beincorporated at an internal position in the compound of the Formula I orFormula II, incorporated at an internal position and at the terminalposition, and various combinations thereof. According to one embodiment,the surface coating provides highly effective anti-fouling surfaces orprevents biofoulants from attaching to the surfaces, and accordingly,provides an effective grafting method that provides substrates withbetter mechanical and chemical robustness and significantly better longterm stability of the substrates.

In addition to the exemplary embodiments, aspects and variationsdescribed above, further embodiments, aspects and variations will becomeapparent by reference to the drawings and figures and by examination ofthe following descriptions.

DETAILED DESCRIPTION OF THE INVENTION Definitions

Unless specifically noted otherwise herein, the definitions of the termsused are standard definitions used in the art of organic synthesis andpharmaceutical sciences. Exemplary embodiments, aspects and variationsare illustrated in the figures, and it is intended that the embodiments,aspects and variations, and the figures disclosed herein are to beconsidered illustrative and not limiting. The entire disclosures of alldocuments cited throughout this application are incorporated herein byreference.

An “alkyl” group is a straight, branched, saturated or unsaturated,aliphatic group having a chain of carbon atoms, optionally with oxygen,nitrogen or sulfur atoms inserted between the carbon atoms in the chainor as indicated. A (C₁₋₂₀)alkyl, for example, includes alkyl groups thathave a chain of between 1 and 20 carbon atoms, and include, for example,the groups methyl, ethyl, propyl, isopropyl, vinyl, allyl, 1-propenyl,isopropenyl, ethynyl, 1-propynyl, 2-propynyl, 1,3-butadienyl,penta-1,3-dienyl, penta-1,4-dienyl, hexa-1,3-dienyl, hexa-1,3,5-trienyl,and the like. An alkyl group may also be represented, for example, as a—(CR¹R₂)_(m)— group where R¹ and R₂ are independently hydrogen or areindependently absent, and for example, m is 1 to 8, and suchrepresentation is also intended to cover both saturated and unsaturatedalkyl groups.

An alkyl as noted with another group such as an aryl group, representedas “arylalkyl” for example, is intended to be a straight, branched,saturated or unsaturated aliphatic divalent group with the number ofatoms indicated in the alkyl group (as in (C₁₋₂₀)alkyl, for example)and/or aryl group (as in (C₅₋₁₄)aryl, for example) or when no atoms areindicated means a bond between the aryl and the alkyl group.Nonexclusive examples of such group include benzyl, phenethyl and thelike.

An “alkylene” group is a straight, branched, saturated or unsaturatedaliphatic divalent group with the number of atoms indicated in the alkylgroup; for example, a —(C₁-C₃)alkylene- or —(C₁-C₃)alkylenyl-.

“Amino acids” (AA) are well known in the art and are compoundscontaining an amine group (—NH₂) and a carboxylic acid group (—COOH),usually functionalized with a side chain for each amino acid. Aminoacids include glycine, alanine, valine, leucine, isoleucine, serine,cysteine, selenocysteine, threonine, methionine, proline, phenylalanine,tyrosine, tryptophan, histidine, lysine, arginine, aspartate, glutamate,asparagine and glutamine. The bonding of two or more amino acids mayform a peptide, such as a dipeptide, tripeptide etc. . . . .

An “aryl” means a monocyclic or polycyclic ring assembly wherein eachring is aromatic, or when fused with one or more rings, forms anaromatic ring assembly. If one or more ring atoms is not carbon (e.g.,N, S), the aryl is a heteroaryl. An aryl group may optionally besubstituted as noted herein.

A “cyclyl” such as a monocyclyl or polycyclyl group includes monocyclic,or linearly fused, angularly fused or bridged polycycloalkyl, orcombinations thereof. Such cyclyl group is intended to include theheterocyclyl analogs. A cyclyl group may be saturated, partiallysaturated or aromatic.

As used herein, a “dental adhesive” or “combined adhesive mixture” meansa compound or composition disclosed herein that may be used as atreatment or pre-treatment on a dental unit or structure (such as atooth) to adhere to a dental element or material (such as an orthodonticappliance (e.g. a bracket)) to a dental surface. The dental adhesive maybe generally referred to as a composition used to adhere an orthodonticappliance to a dental surface, such as a tooth surface. In certainaspects, the dental surface may be pre-treated by etching or priming orby applying an adhesive to enhance adhesion with the compound andcompositions disclosed herein.

A “filler” or “fillers” are particle(s) and/or fibers added to amaterial (plastics, adhesives, composite materials, concrete, cement) tolower the consumption of a more expensive material, such as a binder, orto improve the mechanical properties of the mixed materials. The fillermay be made of various different materials known in the art, includingminerals, e.g., silicate minerals (including mica, silica, glass,kaoline, zirconia etc. . . . ) and biominerals (including calciumcarbonate, silica, hydroxyapatite in tooth and bone), and metal/metaloxides, such as aluminum/alumina, titanium/titania etc. . . . . Fordental applications, a filler or a filler matrix may comprise one filleror a mixture of different fillers. The filler should generally benon-reactive. Representative fillers may include fumed silica, non-acidreactive fluoroaluminosilicate glasses fillers, quartz, ground glasses,non-water-soluble fluorides, silica gels, calcium silicate, zirconiumsilicate, zeolites and molecular sieves.

“Halogen” or “halo” means fluorine, chlorine, bromine or iodine.

A “heterocyclyl” or “heterocycle” is a cycloalkyl wherein one or more ofthe atoms forming the ring is a heteroatom that is a N, O, or S.Non-exclusive examples of heterocyclyl include piperidyl, 4-morpholyl,4-piperazinyl, pyrrolidinyl, 1,4-diazaperhydroepinyl, 1,3-dioxanyl, andthe like.

A “heteroaryl” means a cyclic aromatic group having five or six ringatoms, wherein at least one ring atom is a heteroatom e.g., N, S, O) andthe remaining ring atoms are carbon. Where present, a nitrogen atom canbe optionally quaternerized, and a sulfur atoms can be optionallyoxidized. Heteroaryl groups include, but are not limited to, thosederived from pyridazine, pyridine and pyrimidine. A heteroaryl alsoinclude, but is not limited to, bicyclic or tricyclic rings, where theheteroaryl ring is fused to one or two rings independently selected fromthe group consisting of an aryl ring, a cycloalkyl ring, a cycloalkenylring, and another monocyclic heteroaryl or heterocycloalkyl ring. Thesebicyclic or tricyclic heteroaryls include, but are not limited to, thosederived from benzo[b]furan, benzo[b]thiophene, benzimidazole,indolizine, imidazo[1,2a]pyridine, quinoline, isoquinoline, phthalazine,quinoxaline, naphthyridine, quinolizine, indole, benzoxazole,benzopyrazole and benzothiazole. The bicyclic or tricyclic heteroarylrings can be attached through either the heteroaryl group itself or thearyl, cycloalkyl, cycloalkenyl or heterocycloalkyl group to which it isfused. The heteroaryl groups of this invention can be substituted orunsubstituted as noted.

As used herein, a “mechanical property” or “mechanical properties” of amaterial includes the stiffness, hardness, Young's modulus (elasticmodulus), toughness, strain at fracture (extensibility or flexibility),yield strength, ultimate strength, etc. . . . of a material as disclosedin the application.

“Self assembled” or “self assembly” as used in “self-assembledmonolayer” or SAMs are organic assembly structures that are formed bythe adsorption of molecular compounds from a solution (or a gas phase)onto the surface of substrates or solids. Typically, the adsorbatesorganize spontaneously (sometimes epitaxially) into crystalline orsemi-crystalline-like structures. The molecule (or ligand) such as thecompound of the Formula I, that form SAMs has a chemical functionalitythat may be referred to as a “head group”, with a specific affinity forthe surface of a substrate. Once the head group of the compound binds tothe surface of a substrate, the end group (EG) or tail group forms thesurface of the SAM that may further bind with one or more layers, suchas a second or subsequent self-assembled layer or SAM.

“Substituted or unsubstituted” or “optionally substituted” means that agroup such as, for example, alkyl, aryl, heterocyclyl, (C₁₋₈)cycloalkyl,hetrocyclyl(C₁₋₈)alkyl, aryl(C₁₋₈)alkyl, heteroaryl,heteroaryl(C₁₋₈)alkyl etc. . . . , unless specifically noted otherwise,may be unsubstituted or may substituted by 1, 2 or 3 substituentsselected from the group such as halo, nitro, F₃C—, F₃CO—, CH₃O—,—C(O)OH, —NH₂, —OH, —SH, —NHCH₃, —N(CH₃)₂, —SMe, cyano and the like.

A “substrate” means a material, a base material or composition with asurface for printing and electronics fabrication and devices. Substratesare well known in the art, and may be used interchangeably with“material.”

“Surface primer” or “primer” means a thin layer of material, such as thecompound of the Formula I or Formula II, that may form a self-assembledlayer, such as a SAM, that may be used to improve the adhesion ofsurfaces, such as metals, metal oxides, oxides and other materials, witha second layer of material, such as a second self-assembled layer oranother SAM.

Experimental

The following procedures may be employed for the preparation of thecompounds of the present invention. The starting materials and reagentsused in preparing these compounds are either available from commercialsuppliers such as the Aldrich Chemical Company (Milwaukee, Wis.), Bachem(Torrance, Calif.), Sigma (St. Louis, Mo.), or are prepared by methodswell known to a person of ordinary skill in the art, followingprocedures described in such references as Fieser and Fieser's Reagentsfor Organic Synthesis, vols. 1-17, John Wiley and Sons, New York, N.Y.,1991; Rodd's Chemistry of Carbon Compounds, vols. 1-5 and supps.,Elsevier Science Publishers, 1989; Organic Reactions, vols. 1-40, JohnWiley and Sons, New York, N.Y., 1991; March J.: Advanced OrganicChemistry, 4th ed., John Wiley and Sons, New York, N.Y.; and Larock:Comprehensive Organic Transformations, VCH Publishers, New York, 1989.

In some cases, protective groups may be introduced and finally removed.Suitable protective groups for amino, hydroxy and carboxy groups aredescribed in Greene et al., Protective Groups in Organic Synthesis,Second Edition, John Wiley and Sons, New York, 1991. Standard organicchemical reactions can be achieved by using a number of differentreagents, for examples, as described in Larock: Comprehensive OrganicTransformations, VCH Publishers, New York, 1989.

Preparation of Primers/Compounds:

The compounds may be prepared using conventional organic syntheticmethods known in the art.

The compounds of Scheme 1 and Scheme 2 are prepared under similarreaction conditions, using the starting materials as shown. As shown inScheme 2, the 3,4,5-trihydroxyphenyl propionic acid may be protected bybenzylation using benzyl bromide and a base such as K₂CO₃. Amidation ofthe ester using an amine, such as dimethyl amine and a Grignard, such asisopropyl magnesium chloride, provides the amide. Reduction of the amideusing lithium aluminum hydride provides the amine.

Alternatively, the tetrabenzyl-protected ester may be reduced to thecorresponding alcohol using a hydride, such as diisobutylaluminumhydride. The alcohol may be converted to the corresponding phosphonate.The cyclic phosphate may be treated with an amine at elevatedtemperatures to provide the zwitterionic compound. The tribenzylatedether may be deprotected by hydrogenation with palladium on carbon.

Benzyl 3-(3,4,5-tris(benzyloxy)phenyl)propanoate

Benzyl 3-(3,4,5-tris(benzyloxy)phenyl)propanoate is prepared from thecorresponding acid. A dried 500 ml 3-necked round bottom flask is fittedwith rubber septa and a stir-bar and allowed to cool to room temperature(RT) under an argon flow. One equivalent of the acid is added, followedby 200 ml of anhydrous DMF with stirring. Once dissolved, anhydrousK₂CO₃ (6 equiv) is added with stirring. Fresh benzyl bromide (4.5 equiv)is added via syringe. The solution is placed in an oil bath at 80° C.and stirred for 1 day. The reaction is allowed to cool to RT, and thenpoured through a large fritted glass funnel into a 2 L round bottomflask to remove solids, and the reaction vessel is rinsed 3×300 ml EtOActhrough the frit. The solvent is then removed with a rotary evaporator.Residual DMF is removed by 4 cycles of evaporation with toluene (500ml). The crude residue is then re-dissolved in 1.5 L of Et₂O and washed5×100 ml cold water, 1×500 ml brine, dried over anhydrous Na₂SO₄, andconcentrated under reduced pressure. The crude residue is thendry-loaded onto silica gel and purified by flash chromatography gradientelution 10-40% Et₂O/hexanes. The material is checked for purity by¹H-NMR and then carried on immediately to the next step.

3-(3,4,5-Tris(benzyloxy)phenyl)propanoic acid

3-(3,4,5-Tris(benzyloxy)phenyl)propan-1-ol

The alcohol is prepared from the acid by reduction with LiAlH₄. 7.24grams of acid is dissolved in 100 ml of anhydrous THF and cooled to 0°C. Four equivalent of LiAlH₄ are then added in 4 portions. The reactionis left to stir overnight under argon while warming to RT. The reactionis quenched according to the Fieser workup, diluted with 100 ml of Et₂Oand the aluminum solids filtered off. The solution is transferred to aseparatory funnel, washed once with saturated NaHCO₃, dried overanhydrous Na₂SO₄, filtered, and evaporated under reduced pressure toafford crude material. The crude material is purified on a pad of silicaeluting with Et₂O. The compound is isolated as a clear viscous oil.

Procedure for Preparation of Dimethylamide:

The dimethylamide is conveniently prepared using 1-1′carbonyldiimidazole as peptide coupling reagent. A dried flask is fittedwith a stir bar and rubber septa under argon. One equiv of thecorresponding carboxylic acid, four equiv of anhydrous Et₃N andanhydrous CH₂Cl₂ [0.5M] are added to the flask. The flask is cooled to0° C. in an ice bath and stirred, and 1-1′ carbonyldiimidazole (1.1equiv) is added portion wise. The cooling bath is removed, and thesolution is stirred for 30 minutes while warming to RT. Dimethylamine asthe hydrochloride salt, (2 equiv), is added in one portion and thesolution stirred until TLC indicated completion. The contents aretransferred to a separatory funnel, diluted with CH₂Cl₂, and the organiclayer is washed 2×1N HCl, 2× sat. NaHCO₃ and dried over anhydrousNa₂SO₄. The organic layer is filtered, evaporated under reducedpressure, and the crude residue is filtered over a pad of basic Al₂O₃eluting with EtOAc, evaporated again, and purified by flashchromatography gradient elution with 50-100% EtOAc/hexanes. Thedimethylamide is obtained in high purity (by TLC).

3-(3,4,5-Tris(benzyloxy)phenyl)-N,N-dimethylpropanamide

3-(3,4,5-Tris(benzyloxy)phenyl)-N,N-dimethylpropan-1-amine

Preparation of Benzyl-Protected Compounds by the Chabrier Reaction:

In one method, the benzyl-protected zwitterionic compounds are preparedvia the Chabrier reaction, with certain modifications. Ethylenechlorophosphate (Aesar), stored in a freezer, is used as received. In atypical procedure, a flame-dried flask is fitted with a stir bar, rubbersepta and cooled under positive argon flow. The alcohol is added to theflask followed by anhydrous Et₂O [0.4 M], 1.15 equiv Et₃N and stirred inan ice bath. 1.15 Equiv ethylene chlorophosphate is then added dropwisevia syringe where the amine hydrochloride salt precipitates, and thereaction is stirred for 10 minutes. The flask is allowed to warm to RTwith stirring for 4 hours. Hexanes equal to the volume of Et₂O in theflask, is added to precipitate of the amine hydrochloride salt. Thecontents of the flask are filtered over a pad of basic Celite into aRBF. The contents of the vessel are rinsed with hexanes, and then withEt₂O through the pad of basic Celite, and the solvents are removed underreduced pressure. The content is stored in the RBF under vacuum while asecond reaction vessel is prepared.

A Schlenk-bomb type flask is fitted with a stir bar, flame dried, fittedwith two rubber septa, under argon. The flask containing the phosphateester is back-filled with argon, removed from the vacuum manifold,fitted with a rubber septum, and an argon needle is inserted into theseptum. Anhydrous MeCN (2-4 ml per mmol alcohol) is added to this flaskvia syringe, and swirled until completely dissolved.

The MeCN solution containing the phosphate ester is transferred viasyringe into the Schlenk flask, and the RBF is rinsed once with MeCNinto the Schlenk flask. 2-4 Equiv of the amine are then added to theSchlenk flask, and the rubber septum is replaced with a Schlenk valve.The Schlenk valve is closed and the second rubber septum containing anargon needle is replaced with a glass adaptor and placed under highvacuum. The Schlenk valve is then opened and atmosphere is removed fromthe flask for 10 seconds to remove atmosphere from the flask, theSchlenk valve is then closed, and the flask is refluxed under vacuumwith stirring for 2-4 days at 80° C. in an oil bath.

The flask is removed from the oil bath and allowed to cool to RT. Theflask is then backfilled with argon, removed from the vacuum manifoldand the Schlenk valve is removed. The reaction mixture is transferredvia syringe into a RBF and the reaction vessel is washed 2× with CH₂Cl₂added into the RBF. Volatiles are removed under reduced pressure andresidual solvents are removed by evaporation with pentanes to give thecrude compound. The residue is dissolved in a minimum amount of CH₂Cl₂and purified on C2 bonded reverse phase silica.

Phosphate Intermediate:

The cyclic phosphate intermediate is used immediately after preparationwithout further purification.

The preparation of the corresponding photo-cleavable o-nitrobenzylderivatives may be performed by the similar Chabrier reaction of thecyclic phosphate with a selected functional derivative of theo-nitrobenzyl compound. See, for example, M. S. Kim et al., Bioorganic &Medicinal Chemistry Letters, 16 (2006) 4007-4010.

General Procedure for the De-Protection of Protected Alcohols byHydrogenolysis:

The oxidative stability of each of the zwitterionic compounds containingunprotected alcohols (di-ols, tri-ols, tetra-ols and penta-ols), may beeither in the solid state, a solution in D₆-DMSO, or as a colloidaldispersion in water. Effort is made to exclude atmospheric oxygen duringall manipulations after the protected alcohols had been deprotected. Aspurification of unprotected alcohols may be difficult and requireapplication of purification techniques under inert atmosphere, effort ismade to increase the purity of the intermediates immediately precedingthe de-protection step and the final products are all obtained insatisfactory purity as determined by FTIR, ¹H- and ¹³C-NMR Spectroscopy.

A Schlenk-type flask is fitted with stir bar, fitted with two rubbersepta. 10-20 wt % of Pd/C (5% Pd, Aesar) relative to mass of substrateis added to the flask. A small quantity of CH₂Cl₂ (4-8 ml) is added viasyringe. A separate RBF containing the desired amount of substrate isfitted with a rubber septum and argon needle to purge air out. Theappropriate volume of a 1:1 v/v mixture of CH₂Cl₂/MeOH is added viasyringe. The flask is then swirled until the benzyl-protected compoundis dissolved, and the solution containing the substrate is transferredvia syringe to the Schlenk flask. The RBF is rinsed with MeOH (4-8 ml),and transferred via syringe to the Schlenk flask. The Schlenk valve isthen opened placing the contents of the flask under vacuum and theatmosphere is removed under vacuum. The Schlenk valve is closed, theantechamber before the valve is backfilled with argon and the glassadaptor is replaced with a rubber septum. A hydrogen balloon (doubleballooned) connected to a needle is placed through the septum and then avent needle is placed though the septum to purge argon from theantechamber for 30 seconds then it is removed. The Schlenk valve isopened slowly to allow hydrogen into the reaction vessel and stirring iscontinued for 2-4 days, with periodic replacement of the hydrogenballoon with fresh balloons are used with every replacement.

Once the reaction is completed, the Schlenk valve is closed, and theremaining septum is replaced with a vacuum adaptor connected to a vacuummanifold and the antechamber before the Schlenk valve is placed undervacuum. The Schlenk valve is then opened placing the contents of theflask under vacuum and hydrogen gas is removed from the system in thismanner for 5-10 minutes. A separate round bottom flask, fitted with arubber septum, tared and placed under positive argon flow. The Schlenkflask is then backfilled with argon, and while under positive argon flowthe Schlenk valve is removed and replaced with a rubber septum. A 30 ml,luer lock, PTFE coated syringe is fitted with a long metal needle, andthe syringe is filled and purged with argon 3×, then it is insertedthrough the septum of the reaction vessel. The solution is then drawninto the syringe, along with a blanket of Argon and the metal needle isreplaced with a 0.45 um PTFE syringe filter and disposable needle. Thesolution is then forced through the filter into a RBF to remove Pd/C,and the filtered solution is concentrated under reduced pressure, toafford pure deprotected coacervates, which were stored in a glove boxprotected from oxygen.

Compounds are all characterized by FTIR (cm¹), ¹³C NMR (125 MHz,d₆-DMSO) δ (ppm), ¹H NMR (600 MHz, d₆-DMSO) δ and HRMS, which confirmsthat the anticipated products are produced in satisfactory purity. Thebenzyl-protected coacervates are sufficiently stable for ESI-HRMS (QTOF2Tandem Mass Spectrometer) and are fully characterized prior tohydrogenolysis.

Hydrogenolysis or debenzylation of some of the protected hydroxycompounds is accomplished with a slightly higher catalyst loading (20 wt% of Pd/C relative to mass of starting material) and extended reactiontime (more than 2 days) for complete deprotection, affording thecompounds in greater than 50% yield.

(2-Nitro-1,4-phenylene)bis(methylene) bis(2-methylacrylate)

15 g of finely powdered 1,4-bis(chloromethyl)benzene was added to a 100ml RBF with a large stir bar, and placed in an ice bath. 10 ml of 70%HNO₃ was added slowly and the resulting slurry was allowed toequilibrate to ice bath for 10 minutes. 15 ml of conc. sulfuric acid wasadded dropwise to the slurry over 15 minutes, where the compounddissolved. The mixture was removed from the cooling bath and allowed tocome to RT with efficient stirring for 15 minutes. The flask was placedinto an oil bath preheated to 60° C., and stirred at 60° C. for 2 hours.The flask was removed from the heating bath and cooled to RT, and thecontents were poured onto 450 g of crushed ice/water 1:1. The remainingcontents of the flask were rinsed into the ice water with 50 ml ofwater. The mixture was swirled gently and after all the ice melted, theyellow precipitate was collected by filtration, rinsed with additionalwater, and vacuum dried for several hours by breaking the cake up gentlywith a spatula. The crude material was dried overnight under highvacuum, and then crystallized from EtOH/water, filtered and dried toyield 16.8 g of 1,4-bis(chloromethyl)-2-nitrobenzene as a pale yellowpowder.

4.4 g of 1,4-bis(chloromethyl)-2-nitrobenzene, 4.76 g of sodiummethacrylate and 300 mg of tetra-n-butyl ammonium iodide, and a 2-3 mgof hydroquinone monomethyl ether as radical inhibitor are added to a dry250 ml RBF fitted with a large stir bar under an argon atmosphere. 60 mlof anhydrous DMF were added via syringe with stirring resulting in theformation of a bright red slurry. The flask was placed in an oil bathpreheated to 60° C., and the red slurry stirred under argon at 60° C.for 4 hours. The flask was cooled to RT and the contents poured onto 350ml of crushed ice:water resulting in the formation of a fine pinkprecipitate. The resulting slurry was gently agitated and let stand at0° C. in an ice bath for 15 minutes, and it was rapidly filtered on aglass frit with vacuum, washed with water, and vacuum dried for 3 hours.The resulting pink powder was placed onto a short column packed with 2.5inches of silica on top of 0.5 inches of basic alumina and 300 ml of 25%EtOAc/hexanes was passed through the column into a 500 ml RBF where theorganic solvents were removed in vacuo, and the white residue wasevaporated twice with 100 ml of pentanes to afford 4.8 g (75%) of(2-nitro-1,4-phenylene)bis(methylene) bis(2-methylacrylate) as a whitepowder which was stored under argon and protected from light.

Bis(2-(methacryloyloxy)ethyl)O,O′-((2-nitro-1,4-phenylene)bis(methylene)) disuccinate

10 gm of 2-hydroxyethylmethacrylate, 7.7 gm of succinic anhydride and 50mg of hydroquinone monomethyl ether were added into a 50 ml flask with astir bar. The flask was purged with argon, sealed and heated to 90° C.with stirring for 18 hours. The flask was cooled to RT to afford4-(2-(methacryloyloxy)ethoxy)-4-oxobutanoic acid in quantitative yield.

2.5 gm of 4-(2-(methacryloyloxy)ethoxy)-4-oxobutanoic acid was slowlyadded via syringe to a flask containing 25 ml of anhydrous DMFcontaining 1.5 gm of K₂CO₃ and 160 mg of tetra-n-butyl ammonium iodide.The solution was stirred at RT for 15 minutes. 1.1 gm of1,4-bis(chloromethyl)-2-nitrobenzene was added in one portion, and theflask was resealed and stirred under argon at RT for 18 hours. The crudemixture was poured into a separatory funnel containing 250 ml of EtOAc,and the organic layer was washed 5× with water, 1× with sat. NaHCO₃ 1×,brine, dried over anhydrous magnesium sulfate, and concentrated in vacuoto afford crude material. Flash chromatography eluting with 0-50%EtOAc/hexanes afforded 1.2 gm of pure bis(2-(methacryloyloxy)ethyl)O,O′-((2-nitro-1,4-phenylene)bis(methylene)) disuccinate, as a paleyellow liquid.

The following preparations are as described in Soft Matter, 2011, 7,1426-1440.

2,2′-(2-Nitro-1,4-phenylene)bis(methylene)bis(oxy)bis(oxomethylene)-bis(oxy)bis-(ethane-2,1-diyl)bis(2-methylacrylate):A solution of hydroxyethylmethacrylate (HEMA) (1.9 g, 14 mmol) inanhydrous THF (5 mL) was added dropwise to a solution ofcarbonyldiimidazole (CDI) (2.4 g, 14 mmol) in anhydrous THF (20 mL).After stirring the reaction mixture overnight at RT, a solution of 2NPDM(1.3 g, 7.2 mmol) in anhydrous THF (20 mL) together with a 1.8 mol/Lsodium ethanolate suspension (0.2 mL, 0.35 mmol) was added. Additionalstirring for 5 d at room temperature was followed by filtration andreduction of the filtrate to dryness under reduced pressure. The residuewas purified by column chromatography over silica using CHCl₃/MeOH(20:1) as eluent.

2,2′-(2-Nitro-1,4-phenylene)bis(methylene)bis(oxy)bis(oxomethylene)bis(azane-diyl)bis(ethane-2,1-diyl)bis(2-methylacrylate): 2NPDM (1.0 g,5.5 mmol) was dissolved in anhydrous THF (10 mL) and added dropwise to asolution of 2-isocyanatoethyl methacrylate (1.7 g, 11 mmol) in anhydrousTHF (15 mL) under nitrogen. The reaction mixture was heated to 65° C.and stirred for 24 h at this temperature. When the reaction wascompleted, solvent was evaporated and the residue was purified by columnchromatography over silica using CHCl₃/MeOH (10:1).

Bis(2-(methacryloyloxy)ethyl)-(2-nitro-1,4-phenylene)bis-(methylene)disuccinate: Mono-2-(methacryloyloxy)ethyl succinate (2.5 g, 11 mmol)was dissolved in anhydrous benzene and oxalyl chloride (2.8 g, 2 mmol)was added under nitrogen at room temperature. The reaction mixture washeated to 85° C. and refluxed for 3 h. After cooling to RT, benzene andexcess oxalyl chloride were removed under reduced pressure. The acylchloride obtained was dissolved in anhydrous THF (35 mL) and a solutionof 2NPDM (1.0 g, 5.5 mmol) and triethylamine (1.2 g, 12 mmol) in THF (15mL) was added dropwise. After stirring the mixture overnight at RT,precipitated solids were removed by filtration and the solution wasreduced to dryness. The residue was dissolved in dichloromethane (100mL), washed with water, dried with MgSO₄ and evaporated. The resultingoil was purified by column chromatography over silica using CHCl₃/MeOH(40:1) as eluent.

2-((1-(4-(4-(2-(Methacryloyloxy)ethylcarbamoyloxy)butoxy)-5-methoxy-2-nitro-phenyl)ethoxy)carbonylamino)ethylmethacrylate: 2-Isocyanatoethyl methacrylate (1.1 g, 7.4 mmol) wasdissolved in anhydrous THF (5 mL) and added to a solution of HEMNPBA(1.0 g, 3.5 mmol) and dibutyltin dilaurate (0.11 g, 0.18 mmol) inanhydrous THF (25 mL) under nitrogen. After the mixture was heated to65° C. and stirred for 48 h at this temperature, the reaction wascomplete. Solvent was removed under reduced pressure and the residue waspurified by column chromatography over silica using CHCl₃/MeOH (10:1) aseluent.

AFM images of the primer are obtained at different concentrations: 0.001mM (below its CAC), 0.05 mM (above CAC) and 5 mM. In one example of theprimer, the 5 mM concentration shows a molecularly smooth surfacesuggesting consistent chemical configuration.

Atomic Force Microscopy (AFM) scans of a mica surface adsorbed with acompound of the present application from a solution in DI water ofvarying concentrations (5 mM). The compound forms a defect freeatomically smooth bilayer on mica. No formation of small aggregates onthe surface or thick multilayer is observed.

Surface Coating with Primer Compositions:

Deposition on Substrates for Medical Applications:

The surface coating, priming or deposition of the compound of thepresent application may be performed using standard methods known in theart, with the exception of the particular improved procedures andformulations developed and disclosed herein. For dental and medicalapplications, the primer may be provided in a solvent, such as water,ethanol or a mixture of a solution of water and ethanol. For dentalapplications, the same solvent or different solvent may be used to washthe surface of the tooth or enamel. In certain applications, the solventis water and the process provides an environmentally friendly andeffective process. In some methods using certain monomers, such asdimethacrylates, the solvent may not be needed. In one representativemethod using the compound of the Formula II, such as for compound 94,the use of a solvent in the process is not required. The resultingadhesive bonded or crosslinked under visible light, and then debonded(or cleaved) under UV light with physical stimulus or agitation.

In one application, the solution employed may be used at a neutral pH,or may be maintained in acidic conditions, at a pH<7, pH<6 or pH<5, suchas where phenolic groups, hydroxyphenyl or polyhydroxyphenyl groups arepresent in the monomer to avoid oxidation of the phenols to thecorresponding keto-compounds or quinones. The pH may be adjusted usingan acid, such as phosphoric acid, hydrochloric acid, acetic acid orsulfonic acid. Depending on the type of application or the type ofcompound/primer employed, the pH of the solution may be >pH 5, >pH6, >pH 6.5 or >pH 7. The solution may be degassed using an inert gas orusing vacuum or a combination thereof, and the solution and containerwith the solution may be flushed with an inert gas, such as nitrogen orargon as desired.

Depending on the particular application, the concentration of the primerin the solution may be prepared at different concentrations andconcentration ranges, such as a 0.0001 wt. % to 20 wt. %, 0.0001 wt. %to 15 wt. %, 0.0001 wt. % to 10 wt. %, about 0.001 wt. % to 10 wt. %,about 0.01 wt. % to 10 wt. %, about 0.1 wt. % to 10 wt. % or at about0.1 wt. % to 5 wt. %; at 0.0001 wt %, 0.001 wt. %, 0.01 wt %, 0.1 wt %,1.0 wt %, 5 wt %, 10 wt %, 15 wt %, 20 wt %, 25 wt % or more, in asolvent or solvent mixture. Ethanol, water, ethanol/water or other FDAapproved solvents or solvent mixtures may be used for dental and medicalapplications. However, certain monomers or primers employed do notrequire the use of a solvent.

The bonding or binding of the adhesives of the compound of the Formula Ior Formula II comprising acrylates or methacrylates and related groupson a substrate may be performed using standard methods known in the art.For example, binding may be initiated by photochemical, such asvisible-light-initiated free radical polymerization, and may comprise avisible light photoinitiator, such as camphorquinone (CQ), at forexample, about 0.25 wt %, and another initiator or co-initiator, such as2-dimethylaminoethyl methacrylate (DMAEMA) at, for example, about 1 wt%.

Deposition on Substrates for Materials and Electronics Applications:

In one embodiment, the composition or the solution comprising thecomposition may be applied onto a surface, such as a mineral and/ormetal oxide surface for a period of time to allow the compound/primer toset up or otherwise adsorbed or adhere to the surface. Depending on thenature of the surface and the structure of the compound, adhesion of thecompound to the surface may take less than about 10 minutes, less than 5minutes, less than 3 minutes, less than 2 minutes or less than about 1minute. Once the primer is adsorbed to the surface, any excess primermay be removed from the surface by washing or rising with a solvent orsolvent mixture. For certain applications, the solvent or solventmixture may be water, ethanol, or a mixture of water and ethanolsolution. Depending on the desired application, the surface with theadsorbed primer may be dried using air, heat or a combination thereofuntil the desired dryness is achieved. Depending on the particularapplication, no further processing is required after applying thecomposition to the surfaces.

In some embodiments, the solvent or solvent mixture employed in theprimer solution and/or as a washing solvent may include water, methanol,ethanol, propanol, isopropanol, acetone, methylethyl ketone,dichloromethane, hexanes, cyclohexane, heptane, toluene, xylenes, THF,Me-THF and N-methylpyrrolidone; and various mixtures thereof. In certainapplications, the solvent is water, or a mixture of the solvent(s) withwater, and the process provides an environmentally friendly andeffective process. For certain applications, no solvent is used.

The thickness of the adhered/adsorbed layer may be about 0.5-50 nm,0.1-40 nm, 0.1-30 nm, 0.1-20 nm, 0.1-10 nm, 0.1-5 nm, 0.1-3 nm, 5-10 nm,greater than 20 nm, 100 nm or about 1-10 μm. For deposition of thesolution comprising the compound/primer of the present application, thethickness will depend on the nature of the compound and the desiredthickness of the layer and the nature of the application. For thepreparation of SAMs, the thickness of the adhered/adsorbed layer may beless than for other self-assembled layers with the desired thickness.Optionally, the surface comprising a first layer may be completely driedbefore applying second layer or subsequent layers.

For other materials or electronic applications, the primer may beprovided in a solvent, such as water, ethanol or a mixture of a solutionof water and ethanol; or the solvent or solvent mixture employed in theprimer solution and/or as a washing solvent may include methanol,ethanol, propanol, isopropanol, acetone, methylethyl ketone,dichloromethane, hexane, cyclohexane, heptane, toluene, xylenes, THF,Me-THF and N-methylpyrrolidone; and various mixtures thereof. In onevariation, the same solvent or different solvent may be used to wash thesurface of the substrate. In certain applications, no solvent is usedwith the primer.

In one application, the primer solution employed may be used at aneutral pH, or may be maintained in acidic conditions, at a pH<7, pH<6or pH<5. The pH may be adjusted using an acid, such as phosphoric acid,hydrochloric acid, acetic acid, sulfonic acid, or acidic monomers suchas 10-methacryloyl-decyl-dihydrogen-phosphate (MDP). Depending on thetype of application or the type of compound/primer employed, the pH ofthe solution may be pH>5, pH>6, pH>6.5 or pH>7. The solution may bede-watered using a drying agent or degassed using an inert gas or usingvacuum or a combination thereof, and the solution and container with thesolution may be flushed with an inert gas, such as nitrogen or argon asdesired.

Applications for Adhesive, Composites and Cement:

The treatment of adhesives, coating compositions, composites, paint andsealants with the primer or compounds of the present application issubstantially similar to the methods described above, with standardprocedural modifications known in the art for the treatment of suchmaterials, and applying the advantages of the methods and compositionsdisclosed herein. For applying the method to fillers, for example, themineral and/or metal oxide fillers (powders, fibers etc. . . . ) aretreated with the primer solution.

Fillers, such as pure fillers required as different compositions fordifferent applications, are added to a primer solution. The solution isvigorously stirred and or sonicated for several minutes at about RT. Thefillers are removed or isolated from the solvent, and are rinsed with asolvent or solvent mixture, and then filtered or isolated bycentrifugation. Depending on the nature of the composition and thedesired application, the fillers may be washed and rinsed more than onceas needed. The fillers are then dried, such as by air blowing (fordental applications, for example), or may be dried by a freeze driedprocedure, or dried by hot air, RT air or gas, or dried by vacuum, asknown in the art to the desired level of dryness.

In one particular embodiment, the dried fillers may be added to variousdifferent materials, such as a monomer, a co-monomer mixture,pre-polymer and polymer for performing a polymerizing process with thefillers. In another embodiment as is known in the art, the fillers maybe added to a pre-cement matrix or and adhesive for preparing anadhesive. In another embodiment, the fillers may be combined with acoating, a paint composition, a rubber or plastic, an ink and/or sealantbefore the composition is cured and/or dried. Employing the processesdescribed herein, the mechanical properties (including the hardness,thickness etc. . . . ) of the composite material (with the fillers) maybe significantly increased or improved.

Photo-Cleavage or Debonding of Adhesive or Coating:

The photo-cleavage, photo-decomposition or debonding of the primer,coating or combined adhesive mixture using various irradiation protocolsand methods as known in the art. Irradiation may be performed byspecifically cleaving the primer using infrared (IR), ultraviolet (UV)and/or a combination of IR and UV irradiation for a sufficient period oftime to cleave the primer, coating or adhesive. Depending on the natureof the composition, photo-irradiation may be performed with 265 nm, 300nm, 340 nm, 365 nm, 380 nm or 400 nm, at about RT, for a sufficientperiod of time to debond the primer.

For example, a primer or combined adhesive mixture may be photolyzed byphoto-irradiation, such as with a 10 W UV LED light, a 20 W UV LEDlight, a 130 W UV LED lamp (NobleCure-Altair 75), a 400 W mediumpressure mercury lamp or a portable LX300 UV xenon lamp or for example,with a UV lamp at 340 nm (light intensity=20 mW/cm²), optionally inconjunction with a monochromator at a desired wavelength, such as at 260nm, 340 nm, 365 nm, 380 nm or 400 nm, or as determined based on thenature of the primer or adhesive, for a sufficient period of time, withthe debonding of the material (primer or coating) being monitored untilthe debonding is complete.

Depending on the nature of the primer, composition or combined adhesivemixture, the irradiation may be performed by IR, UV or a combinationthereof. The irradiation may be performed at about RT or above RT, suchas about 27° C., 30° C. or about 35° C. or higher, for a sufficientamount of time to debond the material. In certain embodiments, thedebonding may be performed in conjunction with physical force, such astwisting or moving the substrates to debond, by sonication, orcombinations thereof.

Use of Adhesives and Combined Adhesive Mixtures in Dental Applications:

The following are representative description to demonstrate a procedurefor the use of a dental adhesive of the present application.

Generally, the photocleavable acrylates, such as the photocleavabledimethacrylates of the present application were mixed with a visiblelight photoinitiator such as camphorquinone (CQ, at about 0.25 wt %) andan acrylate such as 2-dimethylaminoethyl methacrylate (DMAEMA, at about1 wt %), and applied on a surface (e.g., a surface of a tooth) as aprimer before applying an adhesive, such as a dental adhesive (alsoreferred to in the art as an adhesive, a resin cement, a sealant or aprimer [or second primer]). In some compositions, the photocleavableacrylates, such as the dimethacrylates (99-50 wt %) were mixed with adental resin mixture (1-50 wt %) of Bis-GMA, TEGMA, DMAEMA, CQ, toenhance its mechanical strength of the visible light cured and UVlight-cleavable primed layer.

When the composition are used as a mixture of the photocleavable primeror adhesive, such as a photocleavable acrylate such as a dimethacrylate,for example, the photocleavable acrylates may comprise of about 10-99 wt% when mixed with a dental adhesive, that may be present in about 90-1wt %. In some mixtures, the photocleavable acrylates comprise of about50 wt %, 60 wt %, 70 wt %, 80 wt %, 90 wt %, 95 wt % or more. In certainmixtures, the adhesive may be present in about 40 wt %, 30 wt %, 20 wt%, 10 wt %, 5 wt %, 3 wt % or about 1 wt %.

For clarity of the compositions referred to herein, in general, a firstcomposition that is applied to a surface is referred to as aphotocleavable monomer composition that may be a single photocleavablemonomer, a mixture of photocleavable monomers or a mixture ofphotocleavable monomer(s) and non-photocleavable monomers (or monomerblends). A second composition that is applied may be referred to as adental adhesive, which may be adhesives or mixtures of adhesives knownin the art. And the combination of the first composition and the dentaladhesive may be referred to as a combined adhesive mixture.

As a representative example of a dental adhesive, Bis-GMA (20 g) andTEGMA (20 g, 18.2 mL) were added to a 100 mL flask. Because Bis-GMA isvery viscous, a heat gun was used to heat the mixture and a homogeneousmixture of Bis-GMA and TEGDMA was obtained. An aliquot (8.8 mL) of themixture was taken to a 20 mL vial. DMAEMA (71 μL) and CQ (33 mg) wereadded to the vial and blended with aid of sonication. The photocleavablemonomer blends (including the photocleavable monomer and the dentalmonomer adhesive mixture) were spread thinly on a surface, such as atooth, metal or mineral surfaces, as a primary adhesive layer.

The dental adhesive was then applied over the primed surface, that is,the surface covered with the photocleavable monomer or monomer blend ormixture, to form the secondary adhesive layer. An object, such as abracket or a dental appliance, is then fitted or mounted on thecombination of two or more adhesive layers. A source of visible light isapplied to the combined adhesive mixture comprising the dental adhesivelayers that consist of a photocleavable adhesive (or primer), dentaladhesive (or dental primer) and dental resin composite (or adhesive) andthe mounted object, for a sufficient period of time to allow theadhesive layer to cure and the object secured to the dental surface.

Depending on the purpose for using the photocleavable adhesive layer,the removal or debonding of the combined adhesive mixture (along withthe coating, cement or sealant) and the object (such as a bracket) maybe performed after a desired period of time. Depending on theapplication, the period of time may be several minutes, several days,several weeks, several months or several years until the purpose andtime for using such combined adhesive mixture is complete.

The debonding or removal of the combined adhesive mixture (coating,cement or sealant) from the surface, such as a tooth surface, may beperformed by exposing the combined adhesive mixture (or photocleavableadhesive or mixtures of adhesives) or area with UV radiation, UV lightor IR light. Optionally, the exposure to UV light may be performed alongwith physical agitation, such as by jiggling, moving, rocking, pullingor prying, vibrating or sonicating for a sufficient period of time todebond or remove the object from the surface.

Depending on the nature of the combined adhesive mixture, the exposureand optionally, the physical agitation, may be performed over a periodof about 30 seconds, about 1 minute, 2 minutes, 3 minutes, 5 minutes orabout 10 minutes or less.

Depending on the nature of the combined adhesive mixture, the strengthof the UV light and the nature of the object mounted on the surface, thephysical agitation (such as sonication), the bonding strength of thecombined adhesive mixture (or the relative amount of effort to remove anobject from the surface) is reduced by up to about 90%, 95% or about 99%(when compared to a process where there is no UV light exposure todebond), allowing for a significantly reduced force (such as jiggling orsonication, for example) to remove the object from the surface.

Representative compounds of the Formula I that may be prepared accordingto the present disclosure is provided in the Table:

TABLE

Compound No. EG— —SP1—SP2—SP3— —Ar—(BG)_(a) 1 —OH—(CH₂)₆—NHC(O)—(CH₂CH₂O)₂—(CH₂)₆—

2 —OH —(CH₂)₆—NHC(O)—(CH₂CH₂O)₂—(CH₂)₆—

3 —OH —(CH₂)₆—NHC(O)—(CH₂CH₂O)₂—(CH₂)₆—

4 —OH —(CH₂CH₂O)₃CH₂CH₂—CONCH₃—(CH₂CH₂O)₃CH₂CH₂—

5 —OH —(CH₂CH₂O)₃CH₂CH₂—CONCH₃—(CH₂CH₂O)₃CH₂CH₂—

6 —OH —(CH₂)₆—OPO₃ ⁻(CH₂)₂—N⁺(CH₃)₂—(CH₂)₆—

7 —OH —(CH₂)₆—OPO₃ ⁻(CH₂)₂—N⁺(CH₃)₂—(CH₂)₆—

8 —OH —(CH₂)₆—OPO₃ ⁻(CH₂)₂—N⁺(CH₃)₂—(CH₂)₆—

9 —OH —(CH₂)₆—OPO₃ ⁻(CH₂)₂—N⁺(CH₃)₂—(CH₂)₆—

10 —SiH₂OH —(CH₂)₆—NHC(O)—(CH₂CH₂O)₂—(CH₂)₆—

11 —SiH₂OH —(CH₂)₆—NHC(O)—(CH₂CH₂O)₂—(CH₂)₆—

12 —SiH₂OH —(CH₂)₆—NHC(O)—(CH₂CH₂O)₂—(CH₂)₆—

13 —SiH₂OH —(CH₂)₆—OPO₃ ⁻(CH₂)₂—N⁺(CH₃)₂—(CH₂)₆—

14 —SiH₂OH —(CH₂)₆—OPO₃ ⁻(CH₂)₂—N⁺(CH₃)₂—(CH₂)₆—

15 —SiH₂OH —(CH₂)₆—OPO₃ ⁻(CH₂)₂—N⁺(CH₃)₂—(CH₂)₆—

16 C₆alkyl —(CH₂)₆—NHC(O)—(CH₂CH₂O)₂—(CH₂)₆—

17 C₆alkyl —(CH₂)₆—NHC(O)—(CH₂CH₂O)₂—(CH₂)₆—

18 C₆alkyl —(CH₂)₆—NHC(O)—(CH₂CH₂O)₂—(CH₂)₆—

19 C₆alkyl —(CH₂)₆—OPO₃ ⁻(CH₂)₂—N⁺(CH₃)₂—(CH₂)₆—

20 C₆alkyl —(CH₂)₆—OPO₃ ⁻(CH₂)₂—N⁺(CH₃)₂—(CH₂)₆—

21 —CF₃ —(CH₂)₆—NHC(O)—(CH₂CH₂O)₂—(CH₂)₆—

22 —CF₃ —(CH₂)₆—NHC(O)—(CH₂CH₂O)₂—(CH₂)₆—

23 —CF₃ —(CH₂)₆—NHC(O)—(CH₂CH₂O)₂—(CH₂)₆—

24 —CF₃ —(CH₂CH₂O)₃CH₂CH₂—CONCH₃—(CH₂CH₂O)₃CH₂CH₂—

25 —CF₃ —(CH₂)₆—OPO₃ ⁻(CH₂)₂—N⁺(CH₃)₂—(CH₂)₆—

26 —CF₃ —(CH₂)₆—OPO₃ ⁻(CH₂)₂—N⁺(CH₃)₂—(CH₂)₆—

27 —CF₃ —(CH₂)₆—OPO₃ ⁻(CH₂)₂—N⁺(CH₃)₂—(CH₂)₆—

28 Phenyl- —(CH₂)₆—NHC(O)—(CH₂CH₂O)₂—(CH₂)₆—

29 Phenyl- —(CH₂)₆—NHC(O)—(CH₂CH₂O)₂—(CH₂)₆—

30 Phenyl- —(CH₂)₆—NHC(O)—(CH₂CH₂O)₂—(CH₂)₆—

31 Phenyl- —(CH₂CH₂O)₃CH₂CH₂—CONCH₃—(CH₂CH₂O)₃CH₂CH₂—

32 Phenyl- —(CH₂CH₂O)₃CH₂CH₂—CONCH₃—(CH₂CH₂O)₃CH₂CH₂—

33 Phenyl- —(CH₂)₆—OPO₃ ⁻(CH₂)₂—N⁺(CH₃)₂—(CH₂)₆—

34 Phenyl- —(CH₂)₆—OPO₃ ⁻(CH₂)₂—N⁺(CH₃)₂—(CH₂)₆—

35 Phenyl- —(CH₂)₆—OPO₃ ⁻(CH₂)₂—N⁺(CH₃)₂—(CH₂)₆—

36 C₆alkyl

37 C₆alkyl

38 HO—

39 Phenyl-

40 Phenyl-

41 CH₂CHCOO—

42 CH₂CHCOO—

43 CH₂CHCOO—

44 CH₂CHCOO—

45 CH₂CHCOO—

Compounds that may be used as co-polymers may also include:

Additional monomers that may be used as co-polymers include:

REFERENCES

-   1. B. K. Ahn, D. W. Lee, J. N. Israelachvili, J. H. Waite,    Surface-initiated self-healing of polymers in aqueous media. Nat    Mater 13, 867-872 (2014); 2. B. K. Ahn, S. Das, R. Linstadt, Y.    Kaufman, N. R. Martinez-Rodriguez, R. Mirshafian, E. Kesselman, Y.    Talmon, B. H. Lipshutz, J. N. Israelachvili, J. H. Waite,    High-performance mussel-inspired adhesives of reduced complexity.    Nat Commun 6, (2015); 3. H. Zeng, D. S. Hwang, J. N.    Israelachvili, J. H. Waite, Strong reversible Fe³⁺-mediated bridging    between dopa-containing protein films in water. Proceedings of the    National Academy of Sciences 107, 12850-12853 (2010). 4. H. Lee, N.    Scherer, P. Messersmith, Single-molecule mechanics of mussel    adhesion. Proc Natl Acad Sci USA, 103, 12999-13003 (2006). 5. M.    Krogsgaard, A. Andersen, H. Birkedal, Gels and threads:    Mussel-inspired one-pot route to advanced responsive materials.    Chemical Communications 50, 13278-13281 (2014). 6. C. N. Z.    Schmitt, Y. Politi, A. Reinecke, M. J. Harrington, Role of    Sacrificial Protein-Metal Bond Exchange in Mussel Byssal Thread    Self-Healing. Biomacromolecules 16, 2852-2861 (2015). 7. F. Zhou et    al., Grafting zwitterionic polymer brushes via electrochemical    surface-initiated atomic-transfer radical polymerization for    anti-fouling applications, J. Mater. Chem. B, 2014,    2, 5352. 8. P. B. Messersmith et al., Universal Surface-Initiated    Polymerization of Antifouling Zwitterionic Brushes Using a    Mussel-Mimetic Peptide Initiator, Langmuir, 2012, 28,    7258-7266. 9. P. B. Messersmith et al., Single-molecule mechanics of    mussel adhesion, PNAS, 103, No. 35, 12999-13003 (2006).

We claim:
 1. A method for bonding a dental object on a surface of atooth comprising: a) preparing the tooth surface for bonding; b)applying a photocleavable adhesive or a mixture of adhesives to thetooth surface; c) contacting the photocleavable adhesive or mixture ofadhesives with a dental adhesive to form a bonding mixture; d)contacting the dental object with the combined adhesive mixture tosecure the dental object onto the surface of the tooth; and e) applyinga source of light to the combined adhesive mixture for a sufficientperiod of time to cure the combined adhesive mixture and secure thedental object onto the tooth surface; wherein the photocleavableadhesive or mixture of adhesives comprise of the surface bindingcompound or mixtures thereof, of the Formula II to the surface:

wherein: m is 1, 2 or 3; n is 1, 2 or 3; i is 1, 2 or 3; each EG and EG1is an end group independently selected from the group consisting of aC₁₋₁₂alkyl, CH₂═CH—, CH₂═C(C₁₋₃alkyl)-, CH₂═CHC(O)—,CH₂═C(C₁₋₃alkyl)C(O)—, CH₂═CHC(O)O—, CH₂═C(C₁₋₃alkyl)C(O)O—,CH₂═C(phenyl)C(O)O—, and CH₂═C(C₁₋₃alkyl)S(O)_(n)O—; each of SP1, SP2and SP3 is a spacer independently selected from the group consisting of—O—, —C(O)—, —S—, —S(O)—, —S(O)₂—, —N—, —NH—, —NCH₃—, —C—, —CH—,—(CH₂)_(q)—, —(CH(OH))_(q)—, —(CH₂CH(OH)CH₂)_(q)—, —(C(CH₃)₂)_(q)—,—(CH(CH₃))_(q)—, —NH(CH₂)₂NH—, —OC(O)—, —CO₂—, —NHCH₂CH₂C(O)—,—OCH₂CH₂C(O)—, —C(O)CH₂CH₂C(O)—, —C(O)NHCH₂CH₂NH—, —NHCH₂C(O)—,—NHC(O)—, —C(O)N—, —NC(O)—, —C(O)NH—, —NCH₃C(O)—, —C(O)NCH₃—,—(CH₂CH₂O)_(p)—, —(CH₂CH₂O)_(p)CH₂CH₂—, —CH₂CH₂—(CH₂CH₂O)_(p)—,—OCH(CH₂O—)₂—, aryl, cyclopentanyl, cyclohexanyl, unsubstitutedphenylenyl and phenylenyl substituted by 1 or 2 substituents selectedfrom the group consisting of halo, CF₃—, CF₃O—, CH₃O—, —C(O)OH,—C(O)OC₁₋₃alkyl, —C(O)CH₃, —CN, —NH₂, —OH, —NHCH₃, —N(CH₃)₂ andC₁₋₃alkyl, p is 1-6, and q is 1-6; provided that: at least one of SP1,SP2 and SP3 is a spacer selected from the group consisting of A, B, C,D, and E:

wherein: Z is C; each E is halo; and e is 0, 1, 2 or 3; and providedthat when EG and EG1 are both CH₂═C(CH₃)C(O)O—(CH₂CH₂)OC(O)— orCH₂═C(CH₃)C(O)NH—(CH₂CH₂)OC(O)—, then the spacer is not

or a compound of the formulae 89 to 96, or mixtures thereof


2. The method of claim 1, further comprising: f) allowing the dentalobject to remain on the tooth surface for a sufficient period of time tobond to the tooth surface and remain for a desired purpose; and g)exposing the combined adhesive mixture with a UV radiation or IRradiation for a sufficient period of time, optionally with physicalagitation of the dental object and or the tooth for a sufficient periodof time, to debond or remove the dental object from the surface.
 3. Themethod of claim 1, wherein each EG and EG1 is independently selectedfrom the group consisting of a C₁₋₁₂alkyl, CH₂═CHC(O)O—,CH₂═C(C₁₋₃alkyl)C(O)O—, CH₂═C(phenyl)C(O)O—, CH₂═C(C₁₋₃alkyl)S(O)_(n)O—,isocyanate, epoxy, oxetanyl, styrenyl, vinyl ether, phenyl and naphthyl.4. The method of claim 1, wherein each EG and EG1 is independentlyselected from the group consisting of N⁺R₁R₂R₃, —PO₄ ⁻, —N⁺R₁R₂R₃X⁻,—PO₄ ⁻Y⁺, —SO₄ ⁻Y⁺, wherein each R₁, R₂ and R₃ is independently H andC₁₋₃alkyl, X⁻ is Cl⁻, Br⁻ and I⁻ and Y⁺ is H⁺ or —^(N+)R¹R²R₃.
 5. Themethod of claim 1, wherein each of SP1, SP2 and SP3 is a spacerindependently selected from the group consisting of —(CH₂)_(q)—,—NH(CH₂)₂NH—, —NHCH₂CH₂C(O)—, —C(O)NHCH₂CH₂NH—, —NHCH₂C(O)—, —NHC(O)—,—C(O)N—, —NC(O)—, —C(O)NH—, —NCH₃C(O)—, —C(O)NCH₃—, —(CH₂CH₂O)_(p)—,—(CH₂CH₂O)_(p)CH₂CH₂—, —CH₂CH₂—(CH₂CH₂O)_(p)— and —OCH(CH₂O—)₂—.